Viscosity Modifiers Comprising Blends of Ethylene-Based Copolymers

ABSTRACT

The present invention is directed to polymer blend compositions for use as viscosity modifiers comprising at least three ethylene-based copolymer components. The viscosity modifiers described herein comprise a first ethylene-based copolymer having an ethylene content of from about 35 to about 55 wt % and/or a heat of fusion of from about 0 to about 30 J/g, a second ethylene-based copolymer having an ethylene content of from about 55 to about 85 wt % and/or a heat of fusion of from about 30 to about 50 J/g, and a third ethylene-based copolymer having an ethylene content of from about 65 to about 85 wt % and/or a heat of fusion of from about 40 to about 70 J/g. The invention is also directed to lubricant compositions comprising a lubricating basestock and a polymer blend as described herein.

PRIORITY CLAIM

This application claims the benefit of and priority to U.S. PatentApplication Ser. No. 61/368,473, entitled “Discrete Ethylene-BasedCopolymers as Viscosity Modifiers” and filed Jul. 28, 2010, which isincorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to polymer blends useful as rheologymodifiers. More particularly, the invention relates to compositionallydisperse and/or crystallinity disperse polymer blends that are useful inmodifying the rheological properties of fluids, wherein the individualcomponents of the polymer blend have large differences in crystallinityand include at least one component having no observable crystallinity.

BACKGROUND OF THE INVENTION

Lubrication fluids are applied between moving surfaces to reducefriction, thereby improving efficiency and reducing wear. Lubricationfluids also often function to dissipate the heat generated by movingsurfaces.

One type of lubrication fluid is a petroleum-based lubrication oil usedfor internal combustion engines. Lubrication oils contain additives thathelp the lubrication oil to have a certain viscosity at a giventemperature. In general, the viscosity of lubrication oils and fluids isinversely dependent upon temperature. When the temperature of alubrication fluid is increased, the viscosity generally decreases, andwhen the temperature is decreased, the viscosity generally increases.For internal combustion engines, for example, it is desirable to have alower viscosity at low temperatures to facilitate engine starting duringcold weather, and a higher viscosity at higher ambient temperatures whenlubrication properties typically decline.

Additives for lubrication fluids and oils include rheology modifiers,such as viscosity index (VI) improvers. VI improving components, many ofwhich are derived from ethylene-alpha-olefin copolymers, modify therheological behavior of a lubricant to increase viscosity and promote amore constant viscosity over the range of temperatures at which thelubricant is used. Higher ethylene content copolymers efficientlypromote oil thickening and shear stability. However, higher ethylenecontent copolymers also tend to flocculate or aggregate in oilformulations leading to extremely viscous and, in the limit, solidformulations. Flocculation typically happens at ambient or subambientconditions of controlled and quiescent cooling. This deleteriousproperty of otherwise advantageous higher ethylene content viscosityimprovers is measured by low temperature solution rheology. Variousremedies have been proposed for these higher ethylene content copolymerformulations to overcome or mitigate the propensity towards theformation of high viscosity flocculated materials.

It is anticipated that the performance of VI improvers can besubstantially improved, as measured by the thickening efficiency (TE)and the shear stability index (SSI), by appropriate and carefulmanipulation of the structure of the VI improver. Particularly, it hasbeen discovered that performance improves when the distribution of themonomers and the chain architecture are controlled and segregated intoat least three compositionally disperse and/or crystallinity dispersepolymeric populations. These disperse polymeric populations may beachieved by the use of a synthesis process that employsmetallocene-based catalysts in the polymerization process.

One proposed solution is the use of blends of amorphous andsemi-crystalline ethylene-based copolymers for lubricant oilformulations. The combination of two such ethylene-propylene copolymersallows for increased thickening efficiency, shear stability index, lowtemperature viscosity performance and pour point. See, e.g., U.S. Pat.Nos. 7,402,235 and 5,391,617, and European Patent 0 638,611, thedisclosures of which are incorporated herein by reference.

There remains a need, however, for novel rheology modifier compositionscomprised of ethylene and alpha-olefin-based comonomers suitable for usein VI improvers which have unexpectedly high thickening efficiencycompared to prior compositions while still being equivalent in theirbeneficial low temperature solution rheology properties. The presentinvention meets this and other needs. The combined components of theinvention deliver a viscosity modifier which does not show an adverseeffect on viscosity due to lowering the temperature from ambient to −35°C. in solution in synthetic and petroleum basestocks.

Contrary to the teachings of the prior art, it has been found that thereis a preferred relationship between the amount and composition of thediscrete distributions of the ethylene-based alpha-olefin copolymersused in the polymeric blends for VI improvers. This relationship leadsto ethylene-based alpha-olefin copolymers having a distribution of atleast three individual ethylene-based copolymers with C₃-C₂₀ alphaolefin comonomers. Each of the individual ethylene-based copolymers(hereinafter components) is a single copolymer made in a singlepolymerization environment having a predefined composition and molecularweight. In one or more embodiments, each of the components is a mostprobable distribution of molecular weights. The components differ in thetheir molecular weight and composition. The invention describes thecombination of these polymers in a predetermined weight ratio such thatthe least crystalline polymer (typically one with the lowest wt %ethylene in the composition of the component) is present in an amount offrom about 15 to about 85 wt %, based on the total weight of thecombination. The balance of the composition comprises two componentswith greater crystallinity and thus a higher wt % ethylene in thecomposition of the components.

The present invention describes the ranges of the composition andcrystallinity for the components of the viscosity modifier. In someembodiments of the invention, the first and second components, when theyare copolymers of ethylene and propylene, are separated by no less than18 wt % ethylene content and the second and third components areseparated by no less than 5 wt % ethylene content. In addition, theleast crystalline polymer has an ethylene content less than 55 wt %,preferably less than 53 wt %.

SUMMARY OF THE INVENTION

The present invention is directed to polymer blend compositions for useas viscosity modifiers comprising at least three ethylene-basedcopolymer components. The viscosity modifiers described herein comprisea first ethylene-based copolymer having an ethylene content of fromabout 35 to about 55 wt % and/or a heat of fusion of from about 0 toabout 30 J/g, a second ethylene-based copolymer having an ethylenecontent of from about 55 to about 85 wt % and/or a heat of fusion offrom about 30 to about 50 J/g, and a third ethylene-based copolymerhaving an ethylene content of from about 65 to about 85 wt % and/or aheat of fusion of from about 40 to about 70 J/g. The invention is alsodirected to lubricant compositions comprising a lubricating basestockand a polymer blend as described herein.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to polymer blends comprising polymercomponents including, but not limited to, compositionally disperseethylene-based copolymers and/or crystallinity disperse ethylene-basedcopolymers that are useful in modifying the rheological properties oflubrication fluids. The compositionally disperse polymer blends areformed from at least three discrete compositions of ethylene-basedcopolymers. The crystallinity disperse polymer blends are formed fromethylene-based copolymers having at least three discrete values ofresidual crystallinity.

The performance of ethylene-based rheology modifiers as viscosity index(VI) improvers are measured by the thickening efficiency (TE) and theshear stability index (SSI), particularly by the ratio of TE to SSI. Itis generally believed that the composition of an olefin copolymer at agiven SSI largely determines the TE, and that higher ethylene content ispreferred because of its inherent TE. While increasing the ethylenecontent of rheology modifiers leads to improved TE/SSI ratios, it alsoleads to increasing crystallinity of the olefin copolymer. Increasingcrystallinity, however, detracts from the performance of a rheologymodifier as a VI improver because crystalline polymers tend toflocculate, either by themselves or in association with other componentsof the lubrication oil, and precipitate out of lubrication oils. Theseprecipitates are apparent as regions (e.g., “lumps”) of high viscosityor essentially complete solidification (e.g., “gels”) and can lead toclogs and blockages of pumps and other passageways for the lubricationfluid and can harm and in some cases cause failure of moving machinery.

While not wishing to be bound by any particular theory, it is believedthat rheology modifiers for lubrication fluids comprising ethylene-basedcopolymers which are compositionally disperse and/or crystallinitydisperse will be less prone to the deleterious effects of macroscopiccrystallization in dilute solution, as measured by the change in therheology of the fluid solution compared to an equivalent amount of asingle ethylene-based copolymer of the same average composition as thedisperse blend. It is also believed that these compositionally and/orcrystallinity disperse components will have lower crystallization oncooling from ambient to sub-ambient temperatures, resulting in betterlow temperature flow properties in solution as compared to equivalentcompositionally uniform polymers of similar molecular weight andthickening efficiency. These polymer blends and their use in lubricationoil compositions with basestocks can be distinguished from othercompositionally non-disperse olefin copolymers by physical separation ofthe compositionally disperse polymer blend into components as well as bya higher ratio of the melting point by DSC to the heat of fusion thanwould be observed for a non-disperse polymer of the same averageethylene content, melt viscosity, and composition.

This invention is directed to a selection of blend compositions for useas viscosity modifiers comprising at least three ethylene-basedcopolymer components. The viscosity modifiers described herein comprisea first ethylene-based copolymer having an ethylene content of fromabout 35 to about 55 wt % and/or a heat of fusion of from about 0 toabout 30 J/g, a second ethylene-based copolymer having an ethylenecontent of from about 55 to about 85 wt % and/or a heat of fusion offrom about 30 to about 50 J/g, and a third ethylene-based copolymerhaving an ethylene content of from about 65 to about 85 wt % and/or aheat of fusion of from about 40 to about 70 J/g. J/g greater than thatof the second copolymer. The three copolymers all have a weight averagemolecular weight (Mw) less than or equal to about 130,000, and MIA/MIBand MIA/MIC are both less than or equal to about 3.0. The invention isalso directed to lubricant compositions comprising a lubricatingbasestock and a polymer blend as described herein.

DEFINITIONS

For purposes of this invention and the claims herein, the definitionsset forth below are used.

As used herein, the term “complex viscosity” means a frequency-dependentviscosity function determined during forced small amplitude harmonicoscillation of shear stress, in units of Pascal-seconds, that is equalto the difference between the dynamic viscosity and the out-of-phaseviscosity (imaginary part of complex viscosity).

As used herein, the term “Composition Distribution Breadth Index” (CDBI)is as defined in U.S. Pat. No. 5,382,630, which is incorporated byreference herein. CDBI is defined as the weight percent of the copolymermolecules having a comonomer content within 50% of the median totalmolar comonomer content. The CDBI of a copolymer is readily determinedutilizing well known techniques for isolating individual fractions of asample of the copolymer. One such technique is Temperature RisingElution Fraction (TREF), as described in L. Wild, et al., J. Poly. Sci.,Poly. Phys. Ed., vol. 20, p. 441 (1982) and U.S. Pat. No. 5,008,204,both of which are incorporated herein by reference.

As used herein, the term “compositionally disperse” means a polymerblend comprised of at least three discrete compositions ofethylene-based copolymers.

As used herein, the term “copolymer” includes any polymer having two ormore monomers.

As used herein, the term “crystallinity disperse” means a polymer blendcomprised of at least three ethylene-based copolymers having discretevalues of residual crystallinity.

As used herein, the term “disperse” means that the compositions includeconstituent polymer fractions which have different compositions and/ordifferent crystallinity due, in part, to different molecular weightdistributions and/or different monomer compositional or sequencedistributions.

As used herein, the term “EA” means the weight percent ofethylene-derived units in the first ethylene-based copolymer based onthe weight of the first ethylene-based copolymer.

As used herein, the term “EB” means the weight percent ofethylene-derived units in the second ethylene-based copolymer based onthe weight of the second ethylene-based copolymer.

As used herein, the term “EC” means the weight percent ofethylene-derived units in the third ethylene-based copolymer based onthe weight of the third ethylene-based copolymer.

As used herein, the term “ethylene-based copolymer” means a copolymercomprised of ethylene and one or more C₃-C₂₀ comonomers.

As used herein, the term “HA” means the heat of fusion in units ofjoules/gram on a first melt of the first ethylene-based copolymer.

As used herein, the term “HB” means the heat of fusion in units ofjoules/gram on the first melt of the second ethylene-based copolymer.

As used herein, the term “HC” means the heat of fusion in units ofjoules/gram on the first melt of the third ethylene-based copolymer.

As used herein, the term “intermolecular composition distribution,”(also “InterCD” or “intermolecular CD”), defines the compositionalheterogeneity in terms of ethylene content, among polymer chains. It isexpressed as the minimum deviation, analogous to a standard deviation,in terms of weight percent ethylene from the average ethylenecomposition for a given copolymer sample needed to include a givenweight percent of the total copolymer sample, which is obtained byexcluding equal weight fractions from both ends of the distribution. Thedeviation need not be symmetrical. When expressed as a single number,for example, an intermolecular composition distribution of 15 wt % shallmean the larger of the positive or negative deviations. For example, at50 wt % intermolecular composition distribution the measurement is akinto conventional composition distribution breadth index.

As used herein, the term “intramolecular composition distribution” (also“IntraCD” or “intramolecular CD”) defines the compositional variation,in terms of ethylene, within a copolymer chain. It is expressed as theratio of the alpha-olefin to ethylene along the segments of the samechain.

As used herein, the term “MIA” means the melt index, in units of g/10min or dg/min, of the first ethylene-based copolymer.

As used herein, the term “MIB” means the melt index, in units of g/10min or dg/min, of the second ethylene-based copolymer.

As used herein, the term “MIC” means the melt index, in units of g/10min or dg/min, of the third ethylene-based copolymer.

As used herein, the term “MnA” means the number-average molecular weightof the first ethylene-based copolymer, as measured by GPC.

As used herein, the term “MnB” means the number-average molecular weightof the second ethylene-based copolymer, as measured by GPC.

As used herein, the term “MnC” means the number-average molecular weightof the third ethylene-based copolymer, as measured by GPC.

As used herein, the term “MwA” means the weight-average molecular weightof the first ethylene-based copolymer in units of grams/mole in terms ofpolystyrene, as measured by GPC.

As used herein, the term “MwB” means the weight-average molecular weightof the second ethylene-based copolymer in units of grams/mole in termsof polystyrene, as measured by GPC.

As used herein, the term “MwC” means the weight-average molecular weightof the third ethylene-based copolymer in units of grams/mole in terms ofpolystyrene, as measured by GPC.

As used herein, the term “MWD” means the molecular weight distribution,or ratio of weight-average molecular weight (Mw) to number-averagemolecular weight (Mn).

As used herein, the term “melting point” means the highest peak amongprincipal and secondary melting peaks as determined by DSC during thesecond melt, as discussed in further detail below.

As used herein, the term “polyene” means monomers or polymers having twoor more unsaturations, e.g., dienes, trienes, and the like.

As used herein, the term “polypropylene” means a polymer made of atleast 50% propylene units, preferably at least 70% propylene units, morepreferably at least 80% propylene units, even more preferably at least90% propylene units, even more preferably at least 95% propylene unitsor 100% propylene units.

As used herein, the term “substantially linear structure” means apolymer characterized as having less than 1 branch point pendant with acarbon chain larger than 19 carbon atoms per 200 carbon atoms along abackbone.

For purposes of this specification and the claims appended thereto, whena polymer or copolymer is referred to as comprising an olefin,including, but not limited to ethylene, propylene, and butene, theolefin present in such polymer or copolymer is the polymerized form ofthe olefin. For example, when a copolymer is said to have an “ethylene”content of 35-55 wt %, it is understood that the mer unit in thecopolymer is derived from ethylene in the polymerization reaction andsaid derived units are present at 35-55 wt %, based upon the weight ofthe copolymer.

Polymer Blends

In some embodiments of the invention, the rheology modifiers forlubrication fluids described herein comprise compositionally dispersepolymer blends and/or crystallinity disperse polymer blends. Thesepolymer blends comprise a first ethylene-based copolymer, a secondethylene-based copolymer, and a third ethylene-based copolymer. Unlessotherwise specified, all references to first ethylene-based copolymer,second ethylene-based copolymer, and third ethylene-based copolymerrefer to both compositionally disperse polymer blends and crystallinitydisperse polymer blends.

The first ethylene-based copolymer, having a relatively lower ethylenecontent, is a copolymer of ethylene, an alpha-olefin comonomer, andoptionally an internal olefin and optionally a polyene, such as a diene.

The second ethylene-based copolymer, having a relatively higher ethylenecontent, is a copolymer of ethylene, an alpha-olefin and optionally aninternal olefin and optionally a polyene, such as a diene.

The third ethylene-based copolymer, having a relatively higher stillethylene content, is a copolymer of ethylene, an alpha-olefin andoptionally an internal olefin and optionally a polyene, such as a diene.

The polymer blends of the invention comprise from about 15 to about 85wt % of a first ethylene-based copolymer, with the balance of the blendcomprising a second ethylene-based copolymer and a third ethylene-basedcopolymer. In some embodiments, the blend comprises from about 25 toabout 75 wt % of the first ethylene-based copolymer and from about 25 toabout 75 wt % of a combination of the second and the thirdethylene-based copolymers. In further embodiments, the blend comprisesfrom about 35 to about 65 wt % of the first ethylene-based copolymer andfrom about 35 to about 65 wt % of a combination of the second and thethird ethylene-based copolymers.

For compositionally disperse polymer blends, the first ethylene-basedcopolymer is characterized by an ethylene weight percent (EA).

For crystallinity disperse polymer blends, the first ethylene-basedcopolymer is characterized by a heat of fusion (HA).

The first ethylene-based copolymer may be further characterized by amelt index (MIA), a number-average molecular weight (MnA), and aweight-average molecular weight (MwA).

In some embodiments, the EA of the first ethylene-based copolymer (in wt%) is in the range of about 35≦EA≦55, or about 40≦EA≦55, or about45≦EA≦53, or about 47≦EA≦52.

In the same or other embodiments, the HA of the first ethylene-basedcopolymer (in J/g) is in the range of about 0≦HA≦30, or about 0≦HA≦15,or about 0≦HA≦10, or about 0≦HA≦5. In some other embodiments, the HA ofthe first ethylene-based copolymer is about 2 J/g.

For compositionally disperse polymer blends, the second ethylene-basedcopolymer is characterized by an ethylene weight percent (EB).

For crystallinity disperse polymer blends, the second ethylene-basedcopolymer is characterized by a heat of fusion (HB).

The second ethylene-based copolymer may be further characterized by amelt index (MIB), a number-average molecular weight (MnB), and aweight-average molecular weight (MwB).

In some embodiments, the EB of the second ethylene-based copolymer (inwt %) is in the range of about 35≦EB≦75, or about 55≦EB≦73, or about65≦EB≦73, or about 67≦EB≦72, or about 67≦EB≦71.

In the same or other embodiments, the HB of the second ethylene-basedcopolymer (in J/g) is in the range of about 30<HB≦50, or about 35<HB≦50,or about 40<HB≦48. In some other embodiments, the HB of the secondethylene-based copolymer is about 45.

In some embodiments of the compositionally disperse polymer blend, theethylene weight percent EA of the first ethylene-based copolymer may beless than the ethylene weight percent EB of the second ethylene-basedcopolymer.

In some embodiments, the compositionally disperse polymer blends may becharacterized by the difference in the ethylene weight percent betweenthe second and first ethylene-based copolymers, EB and EA. In someembodiments, EB−EA≧12, or EB−EA≧17, or EB−EA≧21, or EB−EA≧23. In someembodiments, the difference in ethylene weight percent, EB and EA, is inthe range of about 17≦EB−EA≦23.

For compositionally disperse polymer blends, the third ethylene-basedcopolymer is characterized by an ethylene weight percent (EC).

For crystallinity disperse polymer blends, the third ethylene-basedcopolymer is characterized by a heat of fusion (HC).

In some embodiments, the EC of the third ethylene-based copolymer (in wt%) is in the range of about 65≦EC≦85, or about 70≦EC≦85, or about71≦EC≦85, or about 72≦EC≦83, or about 73≦EC≦81.

In the same or other embodiments, the HC of the third ethylene-basedcopolymer (in J/g) is in the range of about 40≦HC≦85, or about 50≦HC≦80,or about 55≦HC≦75, or about 60≦HC≦75, or about 65≦HC≦75.

In some embodiments of the compositionally disperse polymer blend, theethylene weight percent EB of the second ethylene-based copolymer may beless than the ethylene weight percent EC of the third ethylene-basedcopolymer.

In some embodiments, the compositionally disperse polymer blends may becharacterized by the difference in the ethylene weight percent betweenthe third and second ethylene-based copolymers, EC and EB. In someembodiments, EC−EB≧4, or EC−EB≧6, or EC−EB≧8, or EC−EB≧10. In someembodiments, the difference in ethylene weight percent, EC and EB, is inthe range of 5≦EC−EB≦10.

In some embodiments of the crystallinity disperse polymer blends, theheat of fusion HB of the second ethylene-based copolymer may be lessthan the heat of fusion HC of the third ethylene-based copolymer.

In some embodiments, the crystallinity disperse polymer blends may becharacterized by the difference in the first melt heats of fusion of thethird and second ethylene-based copolymers, HC and HB. In someembodiments, HC−HB≧4, or HC−HB≧8, or HC−HB≧12, or HC−HB≧16. In someembodiments, the difference in the heats of fusion, HC and HB, is in therange of about 8≦HC−HB≦10.

The compositionally disperse and/or crystallinity disperse polymerblends may be further characterized by the ratio of the melt index ofthe second ethylene-based copolymer to the melt index of the thirdethylene-based copolymer, MIB/MIC. In some embodiments, MIB/MIC is lessthan or equal to 3, less than or equal to 2, or less than or equal to 1.

The compositionally disperse and/or crystallinity disperse polymerblends may be further characterized by the absolute value of thedifference in the melt index of the third ethylene-based copolymer, MIC,and the melt index of the second ethylene-based copolymer, MIB. In someembodiments, |MIC−MIB|≦3.0, or |MIC−MIB|≦2.5, or |MIC−MIB|≦2.0, or|MIC−MIB|≦1.5, or |MIC−MIB|≦1.1, or |MIC−MIB|≦1.0.

The first, second, and third ethylene-based copolymers may becharacterized by a weight-average molecular weight (MwA, MwB, and MwC,respectively) of less than or equal to 130,000, or less than 120,000, orless than 110,000, or less than 100,000, or less than 90,000, or lessthan 80,000, or less than 70,000. Preferably, MwA, MwB, and/or MwC arefrom 70,000 to 95,000.

The first, second, and third ethylene-based copolymers may becharacterized by a molecular weight distribution (MWD). Each of thefirst, second, and third ethylene-based copolymers has an MWD of lessthan 3.0, or less than 2.4, or less than 2.2, or less than 2.0.Preferably, the MWD of each copolymer is from about 1.80 to about 1.95.

The MFR of the compositionally disperse and/or crystallinity dispersepolymer blends will be intermediate to the MFR of the lower and higherethylene content copolymers when these copolymers have different MFRs.In some embodiments of the present invention, the first, second, andthird ethylene-based copolymers each have an MFR of from about 0.2 toabout 25.

The first, second, and third ethylene-based copolymers each compriseethylene and one or more comonomers. The comonomers are selected fromthe group consisting of C₃ to C₂₀ alpha-olefins and mixtures thereof.Preferably, the comonomer in each copolymer is propylene, butene,hexene, octene, or mixtures thereof.

In some embodiments, the first, second, or third ethylene-basedcopolymers may each further comprise a polyene monomer. In suchembodiments, each copolymer may further comprise up to 5 mole %, up to 4mole %, up to 3 mole %, up to 2 mole %, or up to 1 mole %polyene-derived units.

In some embodiments, the first, second, and/or third ethylene-basedcopolymer comprises one or more polymer fractions having a different Mn,a different Mw, or a different MWD.

In some embodiments, the first, second, and/or third ethylene-basedcopolymers may have different comonomer insertion sequences.

In some embodiments, the first, second, and/or third ethylene-basedcopolymer of a compositionally disperse polymer blend has asubstantially linear structure.

The substantially linear structure of the first, second, and/or thirdethylene-based copolymer has less than 1 branch point pendant with acarbon chain larger than 19 carbon atoms per 200 carbon atoms along abackbone, less than 1 branch point pendant with a carbon chain largerthan 19 carbon atoms per 300 branch points, less than 1 branch pointpendant with a carbon chain larger than 19 carbon atoms per 500 carbonatoms, or less than 1 branch point pendant with a carbon chain largerthan 19 carbon atoms per 1000 carbon atoms, notwithstanding the presenceof branch points due to incorporation of the comonomer.

The discrete ethylene-based copolymers can be combined such that thefirst ethylene-based copolymer, which is the least crystallineethylene-based copolymer (and typically the ethylene-based copolymerwith the lowest wt % ethylene) can be present in an amount of from about15 to about 85 wt %, based on the combined weight of the first, second,and third ethylene-based copolymers, with the second and thirdethylene-based copolymers together comprising the balance of the blend.In one or more embodiments, the first ethylene-based copolymer can bepresent in an amount from about 25 to about 75 wt %, or about 35 toabout 65 wt %, based on the total weight of the first, second, and thirdcopolymers.

The polymer blend can have an overall concentration or content ofethylene-derived units ranging from about 70 mole % to about 85 mole %.For example, the polymer blend can have a concentration ofethylene-derived units ranging from a low of about 70 mole %, about 72mole %, or about 74 mole % to a high of about 78 mole %, about 80 mole%, about 83 mole %, or about 85 mole %. The MFR of the polymer blend canbe intermediate to the MFR of the lowest and highest ethylene contentcopolymers when the copolymers have different MFRs.

Comonomer Components

Suitable comonomers include, but are not limited to, propylene (C₃) andother alpha-olefins, such as C₄ to C₂₀ alpha-olefins (also referred toherein as “α-olefins”), and preferably propylene and C₄ to C₁₂α-olefins. The α-olefin comonomer can be linear or branched, and two ormore comonomers can be used, if desired. Thus, reference herein to “analpha-olefin comonomer” includes one, two, or more alpha-olefincomonomers.

Examples of suitable comonomers include propylene, linear C₄ to C₁₂α-olefins, and α-olefins having one or more C₁ to C₃ alkyl branches.Specific examples include: propylene; 1-butene; 3-methyl-1-butene;3,3-dimethyl-1-butene; 1-pentene; 1-pentene with one or more methyl,ethyl or propyl substituents; 1-hexene with one or more methyl, ethyl orpropyl substituents; 1-heptene with one or more methyl, ethyl, or propylsubstituents; 1-octene with one or more methyl, ethyl, or propylsubstituents; 1-nonene with one or more methyl, ethyl, or propylsubstituents; ethyl, methyl, or dimethyl-substituted 1-decene, or1-dodecene. Preferred comonomers include: propylene, 1-butene;1-pentene; 3-methyl-1-butene; 1-hexene; 3-methyl-1-pentene;4-methyl-1-pentene; 3,3-dimethyl-1-butene; 1-heptene; 1-hexene with amethyl substituents on any of C₃ to C₅; 1-pentene with two methylsubstituents in any stoichiometrically acceptable combination on C₃ orC₄; 3-ethyl-1-pentene; 1-octene; 1-pentene with a methyl substituents onany of C₃ or C₄; 1-hexene with two methyl substituents in anystoichiometrically acceptable combination on C₃ to C₅; 1-pentene withthree methyl substituents in any stoichiometrically acceptablecombination on C₃ or C₄; 1-hexene with an ethyl substituents on C₃ orC₄; 1-pentene with an ethyl substituents on C₃ and a methyl substituentsin a stoichiometrically acceptable position on C₃ or C₄; 1-decene;1-nonene; 1-nonene with a methyl substituents on any of C₃ to C₉;1-octene with two methyl substituents in any stoichiometricallyacceptable combination on C₃ to C₇; 1-heptene with three methylsubstituents in any stoichiometrically acceptable combination on C₃ toC₆; 1-octene with an ethyl substituents on any of C₃ to C₇; 1-hexenewith two ethyl substituents in any stoichiometrically acceptablecombination on C₃ or C₄; and 1-dodecene.

Other suitable comonomers can include internal olefins. Preferredinternal olefins are cis 2-butene and trans 2-butene. Other internalolefins are contemplated. When an internal olefin is present, negligibleamounts, such as about 2 wt % or less of the total amount of theinternal olefin, can be present in the low ethylene-content copolymer,and most of the internal olefin, such as about 90 wt % or more of thetotal amount of the internal olefin, can be present in the highethylene-content copolymer.

Suitable comonomers can also include one or more polyenes. Suitablepolyenes can include non-conjugated dienes, preferably those that arestraight chain, hydrocarbon di-olefins or cycloalkenyl-substitutedalkenes, having about 6 to about 15 carbon atoms, for example: (a)straight chain acyclic dienes, such as 1,4-hexadiene and 1,6-octadiene;(b) branched chain acyclic dienes, such as 5-methyl-1,4-hexadiene, and3,7-dimethyl-1,6; (c) single ring alicyclic dienes, such as1,4-cyclohexadiene, 1,5-cyclo-octadiene, and 1,7-cyclododecadiene; (d)multi-ring alicyclic fused and bridged ring dienes, such astetrahydroindene, norbornadiene, methyl-tetrahydroindene,dicyclopentadiene (DCPD), bicyclo-(2.2.1)-hepta-2,5-diene, alkenyl,alkylidene, cycloalkenyl and cycloalkylidene norbornenes, such as5-methylene-2-norbornene (MNB), 5-propenyl-2-norbornene,5-isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene,5-cyclohexylidene-2-norbornene, and 5-vinyl-2-norbornene (VNB); and (e)cycloalkenyl-substituted alkenes, such as vinyl cyclohexene, allylcyclohexene, vinyl cyclooctene, 4-vinyl cyclohexene, allyl cyclodecene;and vinyl cyclododecene. Of the non-conjugated dienes typically used,the preferred dienes are dicyclopentadiene (DCPD); 1,4-hexadiene;1,6-octadiene; 5-methyl-1,4-hexadiene; 3,7-dimethyl-1,6-octadiene;5-methylene-2-norbornene; 5-ethylidene-2-norbornene (ENB); andtetracyclo (Δ-11,12) 5,8 dodecene. It is preferred to use dienes that donot lead to the formation of long chain branches, and non- or lowlybranched polymer chains are preferred. Other polyenes that can be usedinclude cyclopentadiene and octatetraene; and the like.

When a polyene is present, the ethylene-based copolymers can include upto 5 mole %, up to 4 mole %, up to 3 mole %, up to 2 mole %, and up to 1mole % polyene-derived units. In some embodiments, the amount ofpolyene, when present, can range from about 0.5 mole % to about 4 mole%; about 1.0 mole % to about 3.8 mole %; or about 1.5 mole % to about2.5 mole %.

Catalyst

The terms “metallocene” and “metallocene catalyst precursor,” as usedherein, refer to compounds possessing a transition metal M, withcyclopentadienyl (Cp) ligands, at least one non-cyclopentadienyl-derivedligand X, and zero or one heteroatom-containing ligand Y, the ligandsbeing coordinated to M and corresponding in number to the valencethereof. The metallocene catalyst precursors are generally neutralcomplexes but when activated with a suitable co-catalyst yield an activemetallocene catalyst, which refers generally to an organometalliccomplex with a vacant coordination site that can coordinate, insert, andpolymerize olefins. The metallocene catalyst precursor is preferably oneof, or a mixture of metallocene compounds, of either or both of thefollowing types:

(1) cyclopentadienyl (Cp) complexes that have two Cp ring systems forligands. The Cp ligands form a sandwich complex with the metal and canbe free to rotate (unbridged) or locked into a rigid configurationthrough a bridging group. The Cp ring ligands can be like or unlikeunsubstituted, substituted, or a derivative thereof such as aheterocyclic ring system, which may be substituted, and thesubstitutions can be fused to form other saturated or unsaturated ringssystems such as tetrahydroindenyl, indenyl, or fluorenyl ring systems.These cyclopentadienyl complexes have the general formula:

(Cp¹R¹ _(m))R³ _(n)(Cp²R² _(p))MX_(q)

where Cp¹ of ligand (Cp¹R¹ _(m)) and Cp¹ of ligand (Cp²R² _(p)) are thesame or different cyclopentadienyl rings; R¹ and R² each is,independently, a halogen or a hydrocarbyl, halocarbyl,hydrocarbyl-substituted organometalloid or halocarbyl-substitutedorganometalloid group containing up to about 20 carbon atoms; m is 0 to5; p is 0 to 5; and two R¹ and/or R² substituents on adjacent carbonatoms of the cyclopentadienyl ring associated there with can be joinedtogether to form a ring containing from 4 to about 20 carbon atoms; R³is a bridging group; n is the number of atoms in the direct chainbetween the two ligands and is 0 to 8, preferably 0 to 3; M is atransition metal having a valence of from 3 to 6, preferably from group4, 5, or 6 of the periodic table of the elements and is preferably inits highest oxidation state; each X is a non-cyclopentadienyl ligand andis, independently, a halogen or a hydrocarbyl, oxyhydrocarbyl,halocarbyl, hydrocarbyl-substituted organometalloid,oxyhydrocarbyl-substituted organometalloid or halocarbyl-substitutedorganometalloid group containing up to about 20 carbon atoms; q is equalto the valence of M minus 2; and

(2) monocyclopentadienyl complexes that have only one Cp ring system asa ligand. The Cp ligand forms a half-sandwich complex with the metal andcan be free to rotate (unbridged) or locked into a rigid configurationthrough a bridging group to a heteroatom-containing ligand. The Cp ringligand can be unsubstituted, substituted, or a derivative thereof suchas a heterocyclic ring system which may be substituted, and thesubstitutions can be fused to form other saturated or unsaturated ringssystems, such as tetrahydroindenyl, indenyl, or fluorenyl ring systems.The heteroatom containing ligand is bound to both the metal andoptionally to the Cp ligand through the bridging group. The heteroatomitself is an atom with a coordination number of three from group VA orVIA of the periodic table of the elements. These mono-cyclopentadienylcomplexes have the general formula:

(Cp¹R¹ _(m))R³ _(n)(Y_(r)R²)MX_(s)

wherein R¹ is, each independently, a halogen or a hydrocarbyl,halocarbyl, hydrocarbyl-substituted organometalloid orhalocarbyl-substituted organometalloid group containing up to about 20carbon atoms; m is 0 to 5; and two R¹ substituents on adjacent carbonatoms of the cyclopentadienyl ring associated therewith can be joinedtogether to form a ring containing from 4 to about 20 carbon atoms; R³is a bridging group; n is 0 to 3; M is a transition metal having avalence of from 3 to 6, preferably from group 4, 5, or 6 of the periodictable of the elements and is preferably in its highest oxidation state;Y is a heteroatom containing group in which the heteroatom is an elementwith a coordination number of three from Group VA or a coordinationnumber of two from group VIA preferably nitrogen, phosphorous, oxygen,or sulfur; R² is a radical selected from a group consisting of C₁ to C₂₀hydrocarbon radicals, substituted C₁ to C₂₀ hydrocarbon radicals, whereone or more hydrogen atoms is replaced with a halogen atom, and when Yis three coordinate and unbridged there may be two R groups on Y eachindependently a radical selected from a group consisting of C₁ to C₂₀hydrocarbon radicals, substituted C₁ to C₂₀ hydrocarbon radicals, whereone or more hydrogen atoms is replaced with a halogen atom, and each Xis a non-cyclopentadienyl ligand and is, independently, a halogen or ahydrocarbyl, oxyhydrocarbyl, halocarbyl, hydrocarbyl-substitutedorganometalloid, oxyhydrocarbyl-substituted organometalloid orhalocarbyl-substituted organometalloid group containing up to about 20carbon atoms; s is equal to the valence of M minus 2.

Examples of suitable biscyclopentadienyl metallocenes of the typedescribed in group 1 above can be as discussed and described in U.S.Pat. Nos. 5,324,800; 5,198,401; 5,278,119; 5,387,568; 5,120,867;5,017,714; 4,871,705; 4,542,199; 4,752,597; 5,132,262; 5,391,629;5,243,001; 5,278,264; 5,296,434; and 5,304,614, which are incorporatedby reference herein.

Noncoordinating Anions

The term “noncoordinating anion” (NCA) means an anion that either doesnot coordinate to the transition metal cation or that is only weaklycoordinated to the cation thereby remaining sufficiently labile to bedisplaced by a neutral Lewis base. “Compatible” noncoordinating anionsare those that are not degraded to neutrality when the initially formedcomplex decomposes. Further, the anion will not transfer an anionicsubstituents or fragment to the cation so as to cause it to form aneutral four coordinate metallocene compound and a neutral by-productfrom the anion. Noncoordinating anions useful in accordance with thisinvention are those that are compatible, stabilize the metallocenecation in the sense of balancing its ionic charge in a +1 state, and yetretain sufficient lability to permit displacement by an ethylenically oracetylenically unsaturated monomer during polymerization. Additionally,the anions useful in this invention will be large or bulky in the senseof sufficient molecular size to largely inhibit or preventneutralization of the metallocene cation by Lewis bases other than thepolymerizable monomers that may be present in the polymerizationprocess. Typically the anion will have a molecular size of greater thanor equal to about 4 angstroms. NCAs are preferred because of theirability to produce a target molecular weight polymer at a highertemperature than tends to be the case with other activation systems suchas alumoxane.

Descriptions of ionic catalysts for coordination polymerization usingmetallocene cations activated by non-coordinating anions appear in theearly work in EP-A-0 277 003; EP-A-0 277 004; WO92/00333; U.S. Pat. Nos.5,198,401 and 5,278,119; which are incorporated by reference herein.These references disclose a preferred method of preparation wheremetallocenes (bisCp and monoCp) are protonated by an anionic precursorssuch that an alkyl/hydride group is abstracted from a transition metalto make it both cationic and charge-balanced by the non-coordinatinganion. The use of ionizing ionic compounds not containing an activeproton but capable of producing both the active metallocene cation and anoncoordinating anion are also known. See, e.g., EP-A-0 426 637, EP-A-0573 403 and U.S. Pat. No. 5,387,568, which are incorporated by referenceherein. Reactive cations other than Bronsted acids capable of ionizingthe metallocene compounds include ferrocenium triphenylcarbonium andtriethylsilylinium cations. Any metal or metalloid capable of forming acoordination complex that is resistant to degradation by water (or otherBronsted or Lewis Acids) may be used or contained in the anion of thesecond activator compound. Suitable metals include, but are not limitedto, aluminum, gold, platinum and the like. Suitable metalloids include,but are not limited to, boron, phosphorus, silicon, and the like.

An additional method for making the ionic catalysts uses ionizinganionic pre-cursors which are initially neutral Lewis acids but form thecation and anion upon ionizing reaction with the metallocene compounds,for example, tris(pentafluorophenyl) boron acts to abstract an alkyl,hydride or silyl ligand to yield a metallocene cation and stabilizingnon-coordinating anion. See, e.g., EP-A-0 427 697 and EP-A-0 520 732,which are incorporated by reference herein. Ionic catalysts for additionpolymerization can also be prepared by oxidation of the metal centers oftransition metal compounds by anionic precursors containing metallicoxidizing groups along with the anion groups. See, e.g., EP-A-0 495 375,which is incorporated by reference here.

Non-Ionic Activators

Where the metal ligands include halide moieties, for example,(methyl-phenyl)silylene(tetra-methyl-cyclopentadienyl)(tert-butyl-amido)zirconiumdichloride, which are not capable of ionizing abstraction under standardconditions, they can be converted via known alkylation reactions withorganometallic compounds such as lithium or aluminum hydrides or alkyls,alkylalumoxanes, Grignard reagents, etc. See, e.g., EP-A-0 500 944,EP-A1-0 570 982 and EP-A1-0 612 768 for processes describing thereaction of alkyl aluminum compounds with dihalide substitutedmetallocene compounds prior to or with the addition of activatinganionic compounds. For example, an aluminum alkyl compound may be mixedwith the metallocene prior to its introduction into the reaction vessel.Since the alkyl aluminum is also suitable as a scavenger its use inexcess of that normally stoichiometrically required for alkylation ofthe metallocene will permit its addition to the reaction solvent withthe metallocene compound. Normally, alumoxane would not be added withthe metallocene so as to avoid premature activation, but can be addeddirectly to the reaction vessel in the presence of the polymerizablemonomers when serving as both scavenger and alkylating activator.Alumoxanes may also fulfill a scavenging function.

Known alkylalumoxanes are additionally suitable as catalyst activators,particularly for those metallocenes comprising halide ligands. Thealumoxane component useful as catalyst activator typically is anoligomeric aluminum compound represented by the general formula(R—Al—O)n, which is a cyclic compound, or R(R—Al—O)nAlR₂, which is alinear compound. In the general alumoxane formula R is a C₁ to C₅ alkylradical, for example, methyl, ethyl, propyl, butyl or pentyl, and “n” isan integer from 1 to about 50. Most preferably, R is methyl and “n” isat least 4, i.e., methylalumoxane (MAO). Alumoxanes can be prepared byvarious procedures known in the art. For example, an aluminum alkyl maybe treated with water dissolved in an inert organic solvent, or it maybe contacted with a hydrated salt, such as hydrated copper sulfatesuspended in an inert organic solvent, to yield an alumoxane. Generally,however prepared, the reaction of an aluminum alkyl with a limitedamount of water yields a mixture of the linear and cyclic species of thealumoxane.

Polymerization Process

Each discrete ethylene-based copolymer can be polymerized in a single,well stirred tank reactor in solution. The viscosity of the solutionduring polymerization can be less than 10000 cPs, or less than 7000 cPs,and preferably less than 500 cPs. The reactor is preferably a liquidfilled, continuous flow, stirred tank reactor providing full back mixingfor random copolymer production. Solvent, monomers, and catalyst(s) arefed to the reactor. When two or more reactors are utilized, solvent,monomers, and/or catalyst(s) is fed to the first reactor or to one ormore additional reactors.

Reactors may be cooled by reactor jackets or cooling coils,autorefrigeration, prechilled feeds or combinations of all three toabsorb the heat of the exothermic polymerization reaction.Autorefrigerated reactor cooling requires the presence of a vapor phasein the reactor. Adiabatic reactors with prechilled feeds are preferredin which the polymerization exotherm is absorbed by permitting atemperature rise of the polymerizing liquid.

Use of hydrogen to control molecular weight may be avoided or reduced,if desired. The reactor temperature may be used to control the molecularweight of the polymer fraction produced. In series operation, this givesrise to a temperature difference between reactors, which is helpful forcontrolling polymer molecular weight.

Reactor temperature can be selected depending upon the effect oftemperature on catalyst deactivation rate and polymer properties and/orextent of monomer depletion. When using more than one reactor, generallytemperatures should not exceed the point at which the concentration ofcatalyst in the second reactor is insufficient to make the desiredpolymer component in the desired amount. Therefore, reaction temperaturecan be determined by the details of the catalyst system.

In general, a single reactor or first reactor in a series will operateat a reactor temperature from about 0° C. to about 200° C., or fromabout 10° C. to about 110° C., or from about 20° C. to about 90° C.Preferably, reaction temperatures are from about 20° C. to about 90° C.or from about 20° C. to about 70° C. When using on or more additionalreactors, the additional reactor temperature will vary from about 40° C.to about 200° C., with about 50° C. to about 140° C. preferred, andabout 60° C. to about 120° C. more preferred. Ranges from any of therecited lower limits to any of the recited upper limits are contemplatedby the inventors and within the scope of the present description. Incopolymerization techniques that utilize one or more bis-Cp catalystswith one or more mono-Cp catalysts, a lower reaction temperature ispreferred for reactions utilizing mono-Cp catalyst when compared to thebis-Cp catalyst.

Reaction pressure is determined by the details of the catalyst system.In general a reactor, whether a single reactor or each of a series ofreactors, operates at a reactor pressure of less than 2500 pounds persquare inch (psi) (17.23 MPa), or less than 2200 psi (15.16 MPa) or lessthan 2000 psi (13.78 MPa). Preferably, reactor pressure is from aboutatmospheric pressure to about 2000 psi (13.78 MPa), or from about 200psi (1.38 MPa) to about 2000 psi (13.78 MPa), or from about 300 psi(2.07 MPa) to about 1800 psi (12.40 MPa). Ranges from any of the recitedlower limits to any of the recited upper limits are contemplated andwithin the scope of the present description.

In the case of less stable catalysts, catalyst can also be fed to asecond reactor when the selected process uses reactors in series.Optimal temperatures can be achieved, particularly for series operationwith progressively increasing polymerization temperature, by using biscyclopentadienyl catalyst systems containing hafnium as the transitionmetal, especially those having a covalent, single atom bridge couplingthe two cyclopentadienyl rings.

Particular reactor configurations and processes suitable for use in theprocesses described herein are described in detail in U.S. Pat. No.6,319,998 and U.S. Provisional Patent Application having Ser. No.60/243,192, filed Oct. 25, 2000, which are incorporated by referenceherein.

Branching is introduced by the choice of polymerization catalysts orprocess. The copolymerization process may occur with or without hydrogenpresent. However, operation without hydrogen is preferred because itinhibits branching in the copolymers since it lead to chain ends whichare completely or substantially saturated. Without being limited bytheory, it is believed that these saturated polymers cannot participatein the principal branching pathway where preformed polymers withunsaturated chain ends are reincorporated into new growing chains, whichlead to branched polymers.

In alternative embodiments, the first, second, and third ethylene-basedcopolymers can be polymerized in an alkane solvent, either hexane in asolution process or propylene in a slurry process and finished to removethe solvent. The first, second, and third ethylene-based copolymers canhave a medium viscosity and a molecular weight in excess of that neededin the final lubricant formulation. For example, most of the traditionalEPDM manufacturing plants cannot “finish” low viscosity polymers havingthe right viscosity for lubricant formulations. In another example, lowviscosity copolymers tend to cold flow upon storage. The second examplecan be particularly true for amorphous copolymers, which have a lowerplateau modulus. The bales are then processed by a series of steps tocreate the final lubricant composition.

In some embodiments, ethylene and a first comonomer can be polymerizedin the presence of a first metallocene catalyst in a firstpolymerization reaction zone under first polymerization conditions toproduce a first effluent comprising a first ethylene-based copolymer.Ethylene and a second comonomer can also be polymerized in the presenceof a second metallocene catalyst in a second polymerization reactionzone under second polymerization conditions to produce a second effluentcomprising a second ethylene-based copolymer. Ethylene and a thirdcomonomer can also be polymerized in the presence of a third metallocenecatalyst in a third polymerization reaction zone under thirdpolymerization conditions to produce a third effluent comprising a thirdethylene-based copolymer. The resulting discrete copolymers can then bemixed or otherwise blended to provide the rheology modifier.

In one or more embodiments, the first and second polymerizationconditions can be independently selected from the group consisting ofslurry phase, solution phase and bulk phase. When the first and secondpolymerization conditions are solution phase, forming the polymer blendcan further include substantial removal of the solvent from the firsteffluent, the second effluent, or both to produce a solid polymer blend.

In one or more embodiments, separate polymerizations can be performed inparallel with the effluent polymer solutions from three reactorscombined downstream before the finishing. In another embodiment,separate polymerizations may be performed in series, where the effluentof one reactor is fed to the next reactor. In still another embodiment,the separate polymerization may be performed in the same reactor,preferably in sequential polymerizations.

The ethylene-based copolymers can be polymerized by a metallocenecatalyst to form the first ethylene-based copolymer in one reactor, thesecond ethylene-based copolymer in another reactor, and the thirdethylene-based copolymer in yet another reactor. The first, second, andthird ethylene-based copolymers can be combined and then subjected tofinishing steps to produce the polymer blend. The first ethylene-basedcopolymer can be made first; alternatively, the second or thirdethylene-based copolymer can be made first in a series reactorconfiguration or all three ethylene-based copolymers can be madesimultaneously in a parallel reactor configuration.

The metallocene catalysts, and their use with non-coordinating ions andnon-ionic activators used in the polymerization process can be asdiscussed and described in U.S. Provisional Patent Application havingSer. No. 61/173,528, entitled “Ethylene-Based Copolymers and LubricatingOil Compositions Containing the Same,” bearing Attorney Docket Number2009EM079-PRV, filed on Apr. 28, 2009, which is incorporated byreference herein.

Examples of suitable bis-cyclopentadienyl metallocenes, include, but arenot limited to the type disclosed in U.S. Pat. Nos. 5,324,800;5,198,401; 5,278,119; 5,387,568; 5,120,867; 5,017,714; 4,871,705;4,542,199; 4,752,597; 5,132,262; 5,391,629; 5,243,001; 5,278,264;5,296,434; and 5,304,614, which are incorporated by reference herein.

Lubrication Oil Composition

Lubricating oil compositions containing the polymer blend and one ormore base oils (or basestocks) are also provided. The basestock can beor include natural or synthetic oils of lubricating viscosity, whetherderived from hydrocracking, hydrogenation, other refining processes,unrefined processes, or re-refined processes. The basestock can be orinclude used oil. Natural oils include animal oils, vegetable oils,mineral oils and mixtures thereof. Synthetic oils include hydrocarbonoils, silicon-based oils, and liquid esters of phosphorus-containingacids. Synthetic oils may be produced by Fischer-Tropsch gas-to-liquidsynthetic procedure as well as other gas-to-liquid oils.

In one embodiment, the basestock is or includes a polyalphaolefin (PAO)including a PAO-2, PAO-4, PAO-5, PAO-6, PAO-7 or PAO-8 (the numericalvalue relating to Kinematic Viscosity at 100° C.). Preferably, thepolyalphaolefin is prepared from dodecene and/or decene. Generally, thepolyalphaolefin suitable as an oil of lubricating viscosity has aviscosity less than that of a PAO-20 or PAO-30 oil. In one or moreembodiments, the basestock can be defined as specified in the AmericanPetroleum Institute (API) Base Oil Interchangeability Guidelines. Forexample, the basestock can be or include an API Group I, II, III, IV,and V oil or mixtures thereof.

In one or more embodiments, the basestock can include oil or blendsthereof conventionally employed as crankcase lubricating oils. Forexample, suitable basestocks can include crankcase lubricating oils forspark-ignited and compression-ignited internal combustion engines, suchas automobile and truck engines, marine and railroad diesel engines, andthe like. Suitable basestocks can also include those oils conventionallyemployed in and/or adapted for use as power transmitting fluids such asautomatic transmission fluids, tractor fluids, universal tractor fluidsand hydraulic fluids, heavy duty hydraulic fluids, power steering fluidsand the like. Suitable basestocks can also be or include gearlubricants, industrial oils, pump oils and other lubricating oils.

In one or more embodiments, the basestock can include not onlyhydrocarbon oils derived from petroleum, but also include syntheticlubricating oils such as esters of dibasic acids; complex esters made byesterification of monobasic acids, polyglycols, dibasic acids andalcohols; polyolefin oils, etc. Thus, the lubricating oil compositionsdescribed can be suitably incorporated into synthetic base oilbasestocks such as alkyl esters of dicarboxylic acids, polyglycols andalcohols; polyalpha-olefins; polybutenes; alkyl benzenes; organic estersof phosphoric acids; polysilicone oils; etc. The lubricating oilcomposition can also be utilized in a concentrate form, such as from 1wt % to 49 wt % in oil, e.g., mineral lubricating oil, for ease ofhandling, and may be prepared in this form by carrying out the reactionof the invention in oil as previously described.

The lubrication oil composition can include a basestock and one or morecompositionally disperse polymer blends and/or one or more crystallinitydisperse polymer blends, and optionally, a pour point depressant. Thelubrication oil composition can have a thickening efficiency greaterthan 1.5, or greater than 1.7, or greater than 1.9, or greater than 2.2,or greater than 2.4 or greater than 2.6. The lubrication oil compositioncan have a shear stability index less than 55, or less than 45, or lessthan 35, or less than 30, or less than 25, or less than 20, or less than15. The lubrication oil composition can have a complex viscosity at −35°C. of less than 500, or less than 450, or less than 300, or less than100, or less than 50, or less 20, or less than 10 centistokes (cSt). Thelubrication oil composition can have a Mini Rotary Viscometer (MRV)viscosity at −35° C. in a 10W-50 formulation of less than 60,000 cpsaccording to ASTM 1678. The lubrication oil composition can have anycombination of desired properties. For example, the lubrication oilcomposition can have a thickening efficiencies greater than about 1.5 orgreater than about 2.6, a shear stability index of less than 55 or lessthan 35 or less than 25, a complex viscosity at −35° C. of less than 500cSt or less than 300 cSt or less than 50 cSt, and/or a Mini RotaryViscometer (MRV) viscosity at −35° C. in a 10W-50 formulation of lessthan about 60,000 cps according to ASTM 1678.

The lubrication oil composition preferably comprises about 2.5 wt %, orabout 1.5 wt %, or about 1.0 wt % or about 0.5 wt % of thecompositionally disperse and/or crystallinity disperse polymer blend. Insome embodiments, the amount of the polymer blend in the lubrication oilcomposition can range from a low of about 0.5 wt %, about 1 wt %, orabout 2 wt % to a high of about 2.5 wt %, about 3 wt %, about 5 wt %, orabout 10 wt %.

Oil Additives

The lubricating oil compositions of the invention can optionally containone or more conventional additives, such as, for example, pour pointdepressants, antiwear agents, antioxidants, other viscosity-indeximprovers, dispersants, corrosion inhibitors, anti-foaming agents,detergents, rust inhibitors, friction modifiers, and the like.

Corrosion inhibitors, also known as anti-corrosive agents, reduce thedegradation of the metallic parts contacted by the lubricating oilcomposition. Illustrative corrosion inhibitors include phosphosulfurizedhydrocarbons and the products obtained by reaction of aphosphosulfurized hydrocarbon with an alkaline earth metal oxide orhydroxide, preferably in the presence of an alkylated phenol or of analkylphenol thioester, and also preferably in the presence of carbondioxide. Phosphosulfurized hydrocarbons are prepared by reacting asuitable hydrocarbon such as a terpene, a heavy petroleum fraction of aC₂ to C₆ olefin polymer such as polyisobutylene, with from 5 to 30 wt %of a sulfide of phosphorus for ½ to 15 hours, at a temperature in therange of 66° C. to 316° C. Neutralization of the phosphosulfurizedhydrocarbon may be effected in the manner known by those skilled in theart.

Oxidation inhibitors, or antioxidants, reduce the tendency of mineraloils to deteriorate in service, as evidenced by the products ofoxidation such as sludge and varnish-like deposits on the metalsurfaces, and by viscosity growth. Such oxidation inhibitors includealkaline earth metal salts of alkylphenolthioesters having C₅ to C₁₂alkyl side chains, e.g., calcium nonylphenate sulfide, bariumoctylphenate sulfide, dioctylphenylamine, phenylalphanaphthylamine,phosphosulfurized or sulfurized hydrocarbons, etc. Other oxidationinhibitors or antioxidants useful in this invention include oil-solublecopper compounds, such as described in U.S. Pat. No. 5,068,047.

Friction modifiers serve to impart the proper friction characteristicsto lubricating oil compositions such as automatic transmission fluids.Representative examples of suitable friction modifiers are found in U.S.Pat. No. 3,933,659, which discloses fatty acid esters and amides; U.S.Pat. No. 4,176,074 which describes molybdenum complexes ofpolyisobutenyl succinic anhydride-amino alkanols; U.S. Pat. No.4,105,571 which discloses glycerol esters of dimerized fatty acids; U.S.Pat. No. 3,779,928 which discloses alkane phosphonic acid salts; U.S.Pat. No. 3,778,375 which discloses reaction products of a phosphonatewith an oleamide; U.S. Pat. No. 3,852,205 which disclosesS-carboxyalkylene hydrocarbyl succinimide, S-carboxyalkylene hydrocarbylsuccinamic acid and mixtures thereof; U.S. Pat. No. 3,879,306 whichdiscloses N(hydroxyalkyl)alkenyl-succinamic acids or succinimides; U.S.Pat. No. 3,932,290 which discloses reaction products of di-(lower alkyl)phosphites and epoxides; and U.S. Pat. No. 4,028,258 which discloses thealkylene oxide adduct of phosphosulfurized N-(hydroxyalkyl)alkenylsuccinimides. Preferred friction modifiers are succinate esters, ormetal salts thereof, of hydrocarbyl substituted succinic acids oranhydrides and thiobis-alkanols, such as described in U.S. Pat. No.4,344,853.

Dispersants maintain oil insolubles, resulting from oxidation duringuse, in suspension in the fluid, thus preventing sludge flocculation andprecipitation or deposition on metal parts. Suitable dispersants includehigh molecular weight N-substituted alkenyl succinimides, the reactionproduct of oil-soluble polyisobutylene succinic anhydride with ethyleneamines such as tetraethylene pentamine and borated salts thereof. Highmolecular weight esters (resulting from the esterification of olefinsubstituted succinic acids with mono or polyhydric aliphatic alcohols)or Mannich bases from high molecular weight alkylated phenols (resultingfrom the condensation of a high molecular weight alkylsubstitutedphenol, an alkylene polyamine and an aldehyde such as formaldehyde) arealso useful as dispersants.

Pour point depressants (“ppd”), otherwise known as lube oil flowimprovers, lower the temperature at which the fluid will flow or can bepoured. Any suitable pour point depressant known in the art can be used.For example, suitable pour point depressants include, but are notlimited to, one or more C₈ to C₁₈ dialkylfumarate vinyl acetatecopolymers, polymethyl methacrylates, alkylmethacrylates and waxnaphthalene.

Foam control can be provided by any one or more anti-foamants. Suitableanti-foamants include polysiloxanes, such as silicone oils andpolydimethyl siloxane.

Anti-wear agents reduce wear of metal parts. Representatives ofconventional antiwear agents are zinc dialkyldithiophosphate and zincdiaryldithiosphate, which also serves as an antioxidant.

Detergents and metal rust inhibitors include the metal salts ofsulphonic acids, alkyl phenols, sulfurized alkyl phenols, alkylsalicylates, naphthenates and other oil soluble mono- and dicarboxylicacids. Highly basic (viz, overbased) metal sales, such as highly basicalkaline earth metal sulfonates (especially Ca and Mg salts) arefrequently used as detergents.

Compositions containing these conventional additives can be blended withthe basestock in amounts effective to provide their normal attendantfunction. Thus, typical formulations can include, in amounts by weight,a VI improver (from about 0.01% to about 12%); a corrosion inhibitor(from about 0.01% to about 5%); an oxidation inhibitor (from about 0.01%to about 5%); depressant (of from about 0.01% to about 5%); ananti-foaming agent (from about 0.001% to about 3%); an anti-wear agent(from about 0.001% to about 5%); a friction modifier (from about 0.01%to about 5%); a detergent/rust inhibitor (from about 0.01 to about 10%);and a base oil.

When other additives are used, it may be desirable, although notnecessary, to prepare additive concentrates that include concentratedsolutions or dispersions of the VI improver (in concentrated amounts),together with one or more of the other additives, such a concentratedenoted an “additive package,” whereby several additives can be addedsimultaneously to the basestock to form a lubrication oil composition.Dissolution of the additive concentrate into the lubrication oil can befacilitated by solvents and by mixing accompanied with mild heating, butthis is not essential. The additive-package can be formulated to containthe VI improver and optional additional additives in proper amounts toprovide the desired concentration in the final formulation when theadditive-package is combined with a predetermined amount of base oil.

Blending with Basestock Oils

Conventional blending methods are described in U.S. Pat. No. 4,464,493,which is incorporated by reference herein. This conventional processrequires passing the polymer through an extruder at elevated temperaturefor degradation of the polymer and circulating hot oil across the dieface of the extruder while reducing the degraded polymer to particlesize upon issuance from the extruder and into the hot oil. Thepelletized, solid polymer compositions of the present invention, asdescribed above, can be added by blending directly with the base oil soas give directly viscosity for the VI improver, so that the complexmulti-step process of the prior art is not needed. The solid polymercomposition can be dissolved in the basestock without the need foradditional shearing and degradation processes.

The polymer compositions will be soluble at room temperature in lubeoils at up to 10 percent concentration in order to prepare a viscositymodifier concentrate. Such concentrates, including eventually anadditional additive package including the typical additives used in lubeoil applications as described above, are generally further diluted tothe final concentration (usually around 1%) by multi-grade lube oilproducers. In this case, the concentrate will be a pourable homogeneoussolid free solution.

The polymer blend compositions preferably have an SSI (determinedaccording to ASTM D97) of from about 10 to about 50.

Specific Embodiments

In one or more specific embodiments, the present invention is directedto a polymer blend composition for use as a VI improver comprising afirst ethylene-based copolymer, a second ethylene-based copolymer, and athird ethylene-based copolymer. The first copolymer has an ethylenecontent from about 35 to about 55 wt %, or from about 40 to about 55 wt%, or from about 45 to about 53 wt %; the second copolymer has anethylene content from about 55 to about 85 wt %, or from about 55 toabout 73 wt %, or from about 65 to about 73 wt %; and the thirdcopolymer has an ethylene content from about 65 to about 85 wt %, orfrom about 70 to about 85 wt %, or from about 71 to about 85 wt %.Additionally, the ethylene content of the second copolymer is at leastabout 15 wt %, or at least about 18 wt %, or at least about 22 wt %greater than that ethylene content of the first copolymer and theethylene content of the third copolymer is at least about 5 wt %, or atleast about 6 wt %, or at least about 8 wt % greater than the ethylenecontent of the second copolymer.

In the same or other embodiments, the first copolymer has a first meltheat of fusion from about 0 to about 30 J/g, or from about 0 to about 15J/g, or from about 0 to about 10 J/g; the second copolymer has a firstmelt heat of fusion from about 30 to about 50 J/g, or from about 35 toabout 48 J/g, or from about 40 to about 48 J/g; and the third copolymerhas a first melt heat of fusion from about 40 to about 85 J/g, or fromabout 55 to about 75 J/g, or from about 65 to about 75 J/g.Additionally, the heat of fusion of the third copolymer is at leastabout 5 J/g, or at least about 8 J/g, or at least about 12 J/g greaterthan that ethylene content of the second copolymer.

Further, the first, second, and third copolymers have a weight-averagemolecular weight (Mw) less than or equal to about 130,000. In the sameor other embodiments, the ratio of the melt index of the first copolymerto the melt index of the second copolymer is less than or equal to about3.0 and the ratio of the melt index of the first copolymer to the meltindex of the third copolymer is less than or equal to about 3.0.Additionally, the composition comprises from about 15 to about 85 wt %,or from about 25 to about 75 wt %, or from about 35 to about 65 wt % ofthe first copolymer, based on the total weight of the first, second, andthird copolymers.

The first, second, and third copolymers of the invention may eachcomprise one or more comonomers selected from the group consisting ofC₃-C₂₀ alpha-olefins.

Further embodiments of the present invention include lubricating oilcompositions comprising a lubricating oil basestock and any of thepolymer blend compositions of the invention described herein.

Polymer Analyses

The ethylene contents as an ethylene weight percent (C₂ wt %) for theethylene-based copolymers were determined according to ASTM D1903.

DSC Measurements of the crystallization temperature, T_(c), and meltingtemperature, T_(m), of the ethylene-based copolymers were measured usinga TA Instruments Model 2910 DSC. Typically, 6-10 mg of a polymer wassealed in a pan with a hermetic lid and loaded into the instrument. In anitrogen environment, the sample was first cooled to −100° C. at 20°C./min. It was then heated to 220° C. at 10° C./min and melting data(first heat) were acquired. This provides information on the meltingbehavior under as-received conditions, which can be influenced bythermal history as well as sample preparation method. The sample wasthen equilibrated at 220° C. to erase its thermal history.Crystallization data (first cool) were acquired by cooling the samplefrom the melt to −100° C. at 10° C./min and equilibrated at −100° C.Finally the sample was heated again to 220° C. at 10° C./min to acquireadditional melting data (second heat). The endothermic meltingtransition (first and second heat) and exothermic crystallizationtransition (first cool) were analyzed for peak temperature and areaunder the peak. The term “melting point,” as used herein, is the highestpeak among principal and secondary melting peaks as determined by DSCduring the second melt, discussed above. The thermal output was recordedas the area under the melting peak of the sample, which was typically ata maximum peak at about 30° C. to about 175° C. and occurred between thetemperatures of about 0° C. and about 200° C. The thermal output wasmeasured in Joules as a measure of the heat of fusion. The melting pointis recorded as the temperature of the greatest heat absorption withinthe range of melting of the sample.

Gelation Visual Test

A 10 ml sample of the solution was placed into a 40 ml glass vial withscrew cap. A typical vial is available from VWR Corporation as catalognumber (VWR cat #: C236-0040). The sample was heated in an 80° C. ovenfor 1 hour to remove any thermal history. The vial was stored at 10° C.for 4 to 6 hours in a Low Temperature Incubator. A typical incubator isavailable from VWR Corporation as catalog number 35960-057. The vial wasthen stored at −15° C.+/−0.5° C. overnight in a chest freezer. A typicalchest freezer is Revco Model UTL 750-3-A30. A thermocouple was placedinto a reference vial, identical to the sample, but containing only thesolvent or base oil to monitor the actual sample temperature. After 16hours the vial was removed from the freezer, while maintaining the capin place and the vial was immediately tilted from about 80° to 90° to analmost horizontal position. If condensation formed on the outside of thevial, the condensation was wiped off with a paper towel. The followingvisual grading was used to rate the sample visually.

GRADE DESCRIPTION DETAILED COMMENTS 0 No gel Free flowing fluid withmirror surface 1 Light gel Slight non-homogeneity, surface roughness 2Medium gel Large non-homogeneity, slight pulling away from vial 3 Heavygel Pulls away from vial, large visible lumps 4 Solid Solid gel

Molecular weight (weight-average molecular weight, Mw, number-averagemolecular weight, Mn, and molecular weight distribution, Mw/Mn or MWD)were determined using a High Temperature Size Exclusion Chromatograph(either from Waters Corporation or Polymer Laboratories), equipped witha differential refractive index detector (DRI), an online lightscattering (LS) detector, and a viscometer. Experimental details notdescribed below, including how the detectors were calibrated, aredescribed in: T. Sun, P. Brant, R. R. Chance, and W. W. Graessley,MACROMOLECULES, Volume 34, Number 19, 6812-6820, (2001).

Three Polymer Laboratories PLgel 10 mm Mixed-B columns were used. Thenominal flow rate was 0.5 cm³/min, and the nominal injection volume was300 μL. The various transfer lines, columns and differentialrefractometer (the DRI detector) were contained in an oven maintained at145° C. Solvent for the SEC experiment was prepared by dissolving 6grams of butylated hydroxy toluene as an antioxidant in 4 liters ofAldrich reagent grade 1, 2, 4 trichlorobenzene (TCB). The TCB mixturewas then filtered through a 0.7 μm glass pre-filter and subsequentlythrough a 0.1 μm Teflon filter. The TCB was then degassed with an onlinedegasser before entering the SEC. Polymer solutions were prepared byplacing dry polymer in a glass container, adding the desired amount ofTCB, then heating the mixture at 160° C. with continuous agitation forabout 2 hours. All quantities were measured gravimetrically. The TCBdensities used to express the polymer concentration in mass/volume unitsare 1.463 g/ml at room temperature and 1.324 g/ml at 145° C. Theinjection concentration ranged from about 1.0 mg/ml to about 2.0 mg/ml,with lower concentrations being used for higher molecular weightsamples. Prior to running each sample the DRI detector and the injectorwere purged. Flow rate in the apparatus was then increased to 0.5ml/minute, and the DRI was allowed to stabilize for about 8 to 9 hoursbefore injecting the first sample. The LS laser was turned on from about1 hour to about 1.5 hours before running samples.

The concentration, c, at each point in the chromatogram is calculatedfrom the baseline-subtracted DRI signal, I_(DRI), using the followingequation:

c=K _(DRI) I _(DRI)/(dn/dc)

where K_(DRI) is a constant determined by calibrating the DRI, and(dn/dc) is the same as described below for the light scattering (LS)analysis. Units on parameters throughout this description of the SECmethod are such that concentration is expressed in g/cm³, molecularweight is expressed in g/mole, and intrinsic viscosity is expressed indL/g.

The light scattering detector used was a Wyatt Technology HighTemperature mini-DAWN. The polymer molecular weight, M, at each point inthe chromatogram is determined by analyzing the LS output using the Zimmmodel for static light scattering (M. B. Huglin, LIGHT SCATTERING FROMPOLYMER SOLUTIONS, Academic Press, 1971):

$\frac{K_{o}c}{\Delta \; {R(\theta)}} = {\frac{1}{{MP}(\theta)} + {2A_{2}c}}$

Here, ΔR(θ) is the measured excess Rayleigh scattering intensity atscattering angle θ, c is the polymer concentration determined from theDRI analysis, A₂ is the second virial coefficient [for purposes of thisinvention and the claims thereto, A₂=0.0006 for propylene polymers and0.001 otherwise], P(θ) is the form factor for a monodisperse random coil(M. B. Huglin, LIGHT SCATTERING FROM POLYMER SOLUTIONS, Academic Press,1971), and K_(o) is the optical constant for the system:

$K_{o} = \frac{4\pi^{2}{n^{2}\left( \frac{n}{c} \right)}^{2}}{\lambda^{4}N_{A}}$

in which N_(A) is Avogadro's number, and (dn/dc) is the refractive indexincrement for the system. The refractive index, n=1.500 for TCB at 145°C. and λ=690 nm. For purposes of this invention and the claims thereto(dn/dc)=0.104 for propylene polymers and 0.1 otherwise.

A high temperature Viscotek Corporation viscometer, which has fourcapillaries arranged in a Wheatstone bridge configuration with twopressure transducers, was used to determine specific viscosity. Onetransducer measures the total pressure drop across the detector, and theother, positioned between the two sides of the bridge, measures adifferential pressure. The specific viscosity, η_(S), for the solutionflowing through the viscometer is calculated from their outputs. Theintrinsic viscosity, [η], at each point in the chromatogram iscalculated from the following equation:

η_(S) =c[η]+0.3(c[η])²

where c is concentration and was determined from the DRI output.

The branching index (g′) is calculated using the output of theSEC-DRI-LS-VIS method as follows. The average intrinsic viscosity,[η]_(avg), of the sample is calculated by:

$\lbrack\eta\rbrack_{avg} = \frac{\sum{c_{i}\lbrack\eta\rbrack}_{i}}{\sum c_{i}}$

where the summations are over the chromatographic slices, i, between theintegration limits.

The branching index g′ is defined as:

$g^{\prime} = \frac{\lbrack\eta\rbrack_{avg}}{{kM}_{v}^{\alpha}}$

where, for purpose of this invention and claims thereto, α=0.695 forethylene, propylene, and butene polymers; and k=0.000579 for ethylenepolymers, k=0.000228 for propylene polymers, and k=0.000181 for butenepolymers. M_(V) is the viscosity-average molecular weight based onmolecular weights determined by LS analysis.

Anton-Parr Low Temperature Solution Rheology (low temperature rheology)experiments were done on an Anton-Parr Model MCR501 rheometer using a 1″cone and plate setup. The cone has a nominal 1 degree angle and 50micron gap. About 100 microliters of sample is deposited on the bottomplate using a syringe-pipette. The cone is then lowered onto the plateso that the volume between the cone and plate is fully occupied bysolution. The temperature is then lowered at a cooling rate of 1.5°C./min. while measuring the complex viscosity at an angular frequency of0.1 radians/sec. applying a 10% strain and recording a value everyminute. The viscosity at 0.1 rad/sec is then plotted as a function oftemperature to observe the effect of gelation.

Scanning Brookfield Viscometer

The Scanning Brookfield Viscometer was operated according to ASTM D5133.25 ml to 30 ml of the sample was poured into a glass stator to the fillline, which was immersed into an oil bath. The oil bath was programmedto cool from −5° C. to −40° C. at 1° C./hour scanning speed. The samplewas preheated to 90° C. for 90 minutes to remove thermal history. Thetemperature ramping program was set to cool from −5° C. to −40° C. at 1°C./hour scanning speed. In sample collection mode, the Gelation Index(GI) and maximum viscosity can be viewed. The torque versus temperaturedata set can be converted to a viscosity-temperature plot at which agelation point and/or corresponding gelation index can be established.

Melt Index (MI) was measured according to ASTM D1238 at 190° C. under a2.16 kilogram load.

Melt Flow Rate (MFR) was measured according to ASTM D1238 at 230° C.under a 2.16 kilogram load or a 21.6 kilogram load.

Thickening Efficiency (TE) was determined according to ASTM D445.

Shear Stability index (SSI) was determined according to ASTM D6278 at 30and 90 cycles using a Kurt Orbahn machine.

Shear stress data was accomplished by first heating the sample to −15°C., and waiting for 15 minutes. Then while measuring the shear stress,applying a logarithmically increasing strain by varying the shear ratelogarithmically from 10⁻³ to 10 with 20 points/decade and 1 second perpoint.

The number of branch points was determined by measuring the radius ofgyration of polymers as a function of the molecular weight by themethods of size exclusion chromatography augmented by laser lightscattering. These procedures are described in the publications “A Studyof the Separation Principle in Size Exclusion Chromatography” by T. Sun,R. R. Chance, W. W. Graessley and D. J. Lohse in the journalMACROMOLECULES, 2004, Volume 37, Issue 11, pp. 4304-4312, and “Effect ofShort Chain Branching on the Coil Dimensions of Polyolefins in DiluteSolution” by T. Sun, R. R. Chance, W. W. Graessley and P. Brant in thejournal MACROMOLECULES, 2001, Volume 34, Issue 19, pp. 6812-6820, whichare incorporated by reference herein.

Branching in polymers having narrow, and most probably, lowpolydispersity index with essentially uniform intramolecular andintermolecular distribution of composition can also be described by theratio of the TE to the MFR@230° C. measured at a load of 2.16 Kg. Highvalues of this parameter indicate low levels of branching while lowlevels indicate substantial levels of branching.

Intermolecular composition distribution, unlike CDBI, contemplatesweight percent of copolymer content within a smaller range from a mediantotal molar comonomer content, e.g., within 25 wt % of median. Forexample, for a Gaussian compositional distribution, 95.5% of thepolymer, used herein for this example as “Polymer Fraction”, is within20 wt % ethylene of the mean if the standard deviation is 10%. Theintermolecular composition distribution for the Polymer Fraction is 20wt % ethylene for such a sample, i.e., 10% standard deviation yields 20wt % intermolecular composition distribution.

Compositional Heterogeneity, both intermolecular-CD andintramolecular-CD can be determined by carbon-13 NMR. Conventionaltechniques for measuring intermolecular-CD and intramolecular-CD aredescribed in MACROMOLECULES, H. N. Cheng, Masahiro Kakugo, entitled“Carbon-13 NMR analysis of compositional heterogeneity inethylene-propylene copolymers,” Volume 24, Issue 8, pp. 1724-1726,(1991), and in the publication MACROMOLECULES, C. Cozewith, entitled“Interpretation of carbon-13 NMR sequence distribution forethylene-propylene copolymers made with heterogeneous catalysts,” Volume20, Issue 6, pp. 1237-1244, (1987).

Generally, conventional carbon-13 NMR measurements of diad and triaddistribution is used to characterize the ethylene-based copolymer. Anyconventional technique for measuring carbon-13 NMR may be utilized. Forexample, ethylene-based copolymer samples are dissolved in a solvent,e.g., trichlorobenzene at 4.5 wt % concentration. The carbon-13 NMRspectra are obtained at elevated temperature, e.g., 140° C., on a NMRspectrometer at 100 MHz. An exemplary spectrometer is a pulsed Fouriertransform Varian XL-400 NMR spectrometer. Deuteriated o-dichlorobenzeneis placed in a coaxial tube to maintain an internal lock signal. Thefollowing instrument conditions are utilized: pulse angle, 75°; pulsedelay, 25 second; acquisition time, 0.5 second, sweep width, 16000 Hz.The carbon-13 NMR peak area measurements were determined by spectralintegration. Diad and triad concentrations were calculated from theequations presented in MACROMOLECULES, Kakugo et al., Volume 15, Issue4, pp. 1150-1152, (1982). The diad and triad concentrations were thennormalized to give a mole fraction distribution. Polymer composition wascalculated from the methane peaks, the methylene peaks, and the diadbalance. These values may be considered individually or an average ofthe three values may be utilized. Unless stated otherwise, thisapplication utilizes an average of these three values. The results arethen compared to conventional model equations as disclosed in the abovereferences.

One aspect of these measurements involves the determination of thereactivity ratios (r₁r₂) of the polymerization system for theethylene-based polymers according to the procedures in the publication.Polymers that have a compositional heterogeneity, either intramolecularor intermolecular, have a much larger reactivity ratio than the polymersthat have only a small or negligible amount.

Without being limited to theory or one method of calculation, it isbelieved that an one exemplary model for, so called idealcopolymerizations, is described by the terminal copolymerization model:

m=M(r ₁ M+1)/(r ₂ +M)  (1)

wherein r₁ and r₂ are the reactivity ratios, m is the ratio of monomersin the copolymer, m₁/m₂, M is the ratio of monomers in the reactor,M₁/M₂, and the diad and triad concentrations follow first order Markovstatistics. For this model, nine equations are derived that related tothe diad and triad concentrations P₁₂ and P₂₁, the probability ofpropylene adding to an ethylene-ended chain, and the probability ofpropylene adding to a propylene-ended chain, respectively. Thus a fit ofcarbon-13 NMR data to these equations yields P₁₂ and P₂₁ as the modelparameters from which r₁ and r₂ can be obtained from the relationships:

r ₁ M=(1−P ₁₂)/P ₁₂

r ₂ /M=(1−P ₂₁)/P ₂₁

The corresponding equations for random copolymerizations with r₁r₂=1 canalso be used to simplify equation (1), above, to m=r₁M. The ethylenefraction in the polymer, E, is equal to 1−P₁₂. This allows the diad andtriad equations to be written in terms of polymer composition:

EE=E ²

EE=2E(1−E)

PP=(1−E)²

EEE=E ³

EEP=2E ²(1−E)

EPE=E ²(1−E)

PEP=E(1−E)²

PPE=2E(1−E)²

PPP=(1−E)³

Variations and extensions of these equations are provided in thereferences incorporated herein, including use of catalysts withdifferent active sites, equations for estimating the number of catalystspecies present, or complex models such as those with three or morespecies present, etc.

From these modeling equations, and those equations presented byMACROMOLECULES, C. Cozewith, Ver Strate, Volume 4, pp. 482-489, (1971),the average values of r₁ , r₂ , and r₁r₂ arising from thecopolymerization kinetics are given by:

r ₁ =(Σr _(1i) f _(i) /G _(i))/(Σf _(i) /G _(i))

r ₂ =(Σr _(2i) f _(i) /G _(i))/(Σf _(i) /G _(i))

r ₁ r ₂ =(Σr _(1i) f _(i) /G _(i))(Σr _(2i) f _(i) /G _(i))/(Σf _(i) /G_(i))²

where G _(i) =r _(1i) M±2+ r _(2i) /M

These equations and the models presented in the references cited abovemay be utilized by those skilled in the art to characterize theethylene-based copolymer composition distribution.

Further information and techniques for measuring intramolecular-CD arefound in MACROMOLECULES, Randel, James C., Volume 11, Issue 1, pp.33-36, (1978), MACROMOLECULES, Cheng, H. N., Volume 17, Issue 10, pp.1950-1955, (1984), and MACROMOLECULES, Ray, G. Joseph, Johnson, Paul E.,and Knox, Jack R., Volume 10 Issue 4, pp. 773-778, (1977), which areincorporated by reference herein. Such techniques are readily known tothose skilled in the art of analyzing and characterizing olefinpolymers.

Temperature Rising Elution Fractionation (TREF). The determination ofintermolecular compositional heterogeneity was determined by thefractionation of the EP copolymer carried out by a Polymer Char TREF 200based on a well-known principle that the solubility of asemi-crystalline copolymer is a strong function of temperature. Acorresponding method is described in U.S. Pat. No. 5,008,204. Theinstrument is a column packed with solid stainless-steel beads. Thecopolymer of interest was dissolved in 1,2 ortho-dichlorobenzene (oDCB)at 160° C. for 60 min. Half of a milliliter (ml) of the polymer solution(concentration=4-5 mg/ml) was injected in the column and it wasstabilized there at 140° C. for 45 min. The solution was cooled from140° C. to −15° C. at 1° C./min and equilibrated at this temperature for10 min. This caused the copolymer to crystallize out of the quiescentsolution in successive layers of decreasing crystallinity onto thesurface of the beads. Pure solvent (oDCB) was pumped for 5 min at −15°C. at a flow rate of 1 ml/min through an infrared detector. A valve wasthen switched to allow this chilled oDCB to flow through the column atthe same flow rate at −15° C. for 10 min. The material eluted wasdesignated as the soluble fraction of the copolymer. At this point, theheater was on and the solvent continued to flow through both the columnand the infrared detector while the temperature was programmed upward ata controlled rate of 2° C./min to 140° C. The infrared detectorcontinuously measured the concentration of the copolymer in the effluentfrom the column, and a continuous solubility distribution curve wasobtained.

Described below are further embodiments of the inventions providedherein:

A. A polymer blend composition comprising a first ethylene-basedcopolymer, a second ethylene-based copolymer, and a third ethylene-basedcopolymer, wherein the first copolymer has an ethylene content fromabout 35 to about 55 wt %; the second copolymer has an ethylene contentfrom about 55 to about 85 wt %; the third copolymer has an ethylenecontent from about 65 to about 85 wt %; the ethylene content of thesecond copolymer is at least about 15 wt % greater than the ethylenecontent of the first copolymer and the ethylene content of the thirdcopolymer is at least about 5 wt % greater than the ethylene content ofthe second copolymer; the first, second, and third copolymers have aweight-average molecular weight (Mw) less than or equal to about130,000; the ratio of the melt index of the first copolymer to the meltindex of the second copolymer is less than or equal to about 3.0 and theratio of the melt index of the first copolymer to the melt index of thethird copolymer is less than or equal to about 3.0; and the compositioncomprises from about 15 to about 85 wt % of the first copolymer, basedon the total weight of the first, second, and third copolymers.B. The polymer blend composition of paragraph A, wherein the firstcopolymer has an ethylene content from about 40 to about 55 wt %, thesecond copolymer has an ethylene content from about 55 to about 73 wt %,and the third copolymer has an ethylene content from about 70 to about85 wt %.C. The polymer blend composition of any of paragraphs A and B, whereinthe first copolymer has an ethylene content from about 45 to about 53 wt%, the second copolymer has an ethylene content from about 65 to about73 wt %, and the third copolymer has an ethylene content from about 71to about 85 wt %.D. The polymer blend composition of any of paragraphs A through C,wherein the first, second, and third copolymers each comprise one ormore comonomers selected from the group consisting of C₃-C₂₀alpha-olefins.E. The polymer blend composition of any of paragraphs A through D,wherein the ethylene content of the second copolymer is at least about18 wt % greater than the ethylene content of the first copolymer and theethylene content of the third copolymer is at least about 6 wt % greaterthan the ethylene content of the second copolymer.F. The polymer blend composition of any of paragraphs A through E,wherein the ethylene content of the second copolymer is at least about22 wt % greater than the ethylene content of the first copolymer and theethylene content of the third copolymer is at least about 8 wt % greaterthan the ethylene content of the second copolymer.G. The polymer blend composition of any of paragraphs A through F,wherein the composition comprises from about 25 to about 75 wt % of thefirst copolymer, based on the total weight of the first, second, andthird copolymers.H. The polymer blend composition of claim 7 any of paragraphs A throughG, wherein the composition comprises from about 35 to about 65 wt % ofthe first copolymer, based on the total weight of the first, second, andthird copolymers.I. A polymer blend composition comprising a first ethylene-basedcopolymer, a second ethylene-based copolymer, and a third ethylene-basedcopolymer, wherein the first copolymer has a first melt heat of fusionfrom about 0 to about 30 J/g; the second copolymer has a first melt heatof fusion from about 30 to about 50 J/g; the third copolymer has a firstmelt heat of fusion from about 40 to about 85 J/g; the heat of fusion ofthe third copolymer is at least about 5 J/g greater than the heat offusion of the second copolymer; the first, second, and third copolymershave a weight-average molecular weight (Mw) less than or equal to about130,000; the ratio of the melt index of the first copolymer to the meltindex of the second copolymer is less than or equal to about 3.0 and theratio of the melt index of the first copolymer to the melt index of thethird copolymer is less than or equal to about 3.0; and the compositioncomprises from about 15 to about 85 wt % of the first copolymer, basedon the total weight of the first, second, and third copolymers.J. The polymer blend composition of any of paragraphs A through I,wherein the first copolymer has a first melt heat of fusion from about 0to about 15 J/g, the second copolymer has a first melt heat of fusionfrom about 35 to about 48 J/g, and the third copolymer has a first meltheat of fusion from about 55 to about 75 J/g.K. The polymer blend composition of any of paragraphs A through J,wherein the first copolymer has a first melt heat of fusion from about 0to about 10 J/g, the second copolymer has a first melt heat of fusionfrom about 40 to about 48 J/g, and the third copolymer has a first meltheat of fusion from about 65 to about 75 J/g.L. The polymer blend composition of any of paragraphs A through K,wherein the first, second, and third copolymers each comprise one ormore comonomers selected from the group consisting of C₃-C₂₀alpha-olefins.M. The polymer blend composition of any of paragraphs A through L,wherein the heat of fusion of the third copolymer is at least about 8J/g greater than the heat of fusion of the second copolymer.N. The polymer blend composition of any of paragraphs A through M,wherein the heat of fusion of the third copolymer is at least about 12J/g greater than the heat of fusion of the second copolymer.O. The polymer blend composition of any of paragraphs A through N,wherein the composition comprises from about 25 to about 75 wt % of thefirst copolymer, based on the total weight of the first, second, andthird copolymers.P. The polymer blend composition of any of paragraphs A through 0,wherein the composition comprises from about 35 to about 65 wt % of thefirst copolymer, based on the total weight of the first, second, andthird copolymers.Q. A lubricating oil composition comprising a lubricating oil basestock,a first ethylene-based copolymer, a second ethylene-based copolymer, anda third ethylene-based copolymer wherein the first copolymer has anethylene content from about 35 to about 55 wt %; the second copolymerhas an ethylene content from about 55 to about 85 wt %; the thirdcopolymer has an ethylene content from about 65 to about 85 wt %; theethylene content of the third copolymer is at least about 5 wt % greaterthan the ethylene content of the second copolymer; the first, second,and third copolymers have a weight-average molecular weight (Mw) lessthan or equal to about 130,000; the ratio of the melt index of the firstcopolymer to the melt index of the second copolymer is less than orequal to about 3.0 and the ratio of the melt index of the firstcopolymer to the melt index of the third copolymer is less than or equalto about 3.0; and the composition comprises from about 15 to about 85 wt% of the first copolymer, based on the total weight of the first,second, and third copolymers.R. The lubricating oil composition of paragraph Q, wherein the firstcopolymer has an ethylene content from about 45 to about 53 wt %, thesecond copolymer has an ethylene content from about 65 to about 73 wt %,and the third copolymer has an ethylene content from about 71 to about85 wt %.S. The lubricating oil composition of any of paragraphs Q or R, whereinthe first, second, and third copolymers each comprise one or morecomonomers selected from the group consisting of C₃-C₂₀ alpha-olefins.T. The lubricating oil composition of any of paragraphs Q through S,wherein the ethylene content of the second copolymer is at least about18 wt % greater than the ethylene content of the first copolymer and theethylene content of the third copolymer is at least about 6 wt % greaterthan the ethylene content of the second copolymer.U. A lubricating oil composition comprising a lubricating oil basestock,a first ethylene-based copolymer, a second ethylene-based copolymer, anda third ethylene-based copolymer, wherein the first copolymer has afirst melt heat of fusion from about 0 to about 30 J/g; the secondcopolymer has a first melt heat of fusion from about 30 to about 50 J/g;the third copolymer has a first melt heat of fusion from about 40 toabout 85 J/g; the heat of fusion of the third copolymer is at leastabout 5 J/g greater than the heat of fusion of the second copolymer; thefirst, second, and third copolymers have a weight-average molecularweight (Mw) less than or equal to about 130,000; the ratio of the meltindex of the first copolymer to the melt index of the second copolymeris less than or equal to about 3.0 and the ratio of the melt index ofthe first copolymer to the melt index of the third copolymer is lessthan or equal to about 3.0; and the composition comprises from about 15to about 85 wt % of the first copolymer, based on the total weight ofthe first, second, and third copolymers.V. The lubricating oil composition of any of paragraphs Q through U,wherein the first copolymer has a first melt heat of fusion from about 0to about 10 J/g, the second copolymer has a first melt heat of fusionfrom about 40 to about 48 J/g, and the third copolymer has a first meltheat of fusion from about 65 to about 75 J/g.W. The lubricating oil composition of any of paragraphs Q through V,wherein the first, second, and third copolymers each comprise one ormore comonomers selected from the group consisting of C₃-C₂₀alpha-olefins.X. The lubricating oil composition of any of paragraphs Q through W,wherein the ethylene content of the second copolymer is at least about18 wt % greater than the ethylene content of the first copolymer and theethylene content of the third copolymer is at least about 6 wt % greaterthan the ethylene content of the second copolymer.

EXAMPLES Preparation of the Ethylene-Based Copolymers

A variety of ethylene-based copolymers as described above weresynthesized as follows. Ethylene and propylene were polymerized insolution in a continuous stirred tank reactor, using hexane as asolvent. Polymerization in the reactor was performed at a temperature ofabout 110-115° C., an overall pressure of about 20 bar, and ethylene andpropylene feed rates of about 1.3 and 2.0 kg/hr, respectively.N,N-dimethylanilinium tetrakis(pentafluorophenyl)boron was used toactivatedi(p-triethylsilylphenyl)methenyl[cyclopentadienyl)(2,7-di-tert-butylfluorophenyl)]hafniumdimethyl as the catalyst. During the polymerization process, hydrogenaddition and temperature control were used to achieve the desired meltflow rate. The catalyst, activated externally to the reactor, was addedas needed in amounts effective to maintain the target polymerizationtemperature.

The copolymer solution exiting the reactor was stopped from furtherpolymerization by the addition of water and then devolatilized usingconventional techniques such as, for example, flashing or liquid phaseseparation, first by removing the bulk of the hexane to provide aconcentrated solution, then by stripping the remainder of the solvent inanhydrous conditions using a devolatilizer or a twin screwdevolatilizing extruder so as to result in a molten polymer compositioncomprising less than 0.5 wt % solvent and other volatiles. The moltenpolymer was cooled until solid.

The compositions and other properties of the polymers thus prepared areset forth in Table 1. Polymers that meet the description of the firstethylene-based copolymer as described above are designated “EA,”polymers that meet the description of the second ethylene-basedcopolymer as described above are designated “EB,” and polymers that meetthe description of the third ethylene-based polymer are designated “EC.”

TABLE 1 EA1 EA2 EB1 EB2 EC1 EC2 EC3 Mw, g/mol 92958 96720 74883 7789065983 94434 80194 Mw/Mn 2.25 2.20 2.28 2.24 2.23 2.23 2.18 C₂, wt %48.98 45.65 70.41 66.82 72.57 76.42 79.28 MFR, g/10 min 5.53 5.97 6.404.99 8.32 1.49 2.64 (2.16 kg, 230° C.) Tm, ° C. (1^(st) melt) −35.0 n/a43.6 15.0 44.8 48.6 55.5 Hf, J/g (1^(st) melt) 0.4 n/a 45.0 44.0 58.570.4 73.6 Tc, ° C. (2^(nd) cool) −50.6 n/a 14.6 11.6 18.5 37.9 44.6 Hc,J/g (2^(nd) cool) 2.4 n/a 46.4 36.2 52.1 61.4 59.6 Tm, ° C. (2^(nd)melt) −36.4 n/a 19.2 11.0 30.2 48.5 53.8 Hf, J/g (2^(nd) melt) 0.6 n/a46.5 43.3 51.2 63.5 67.9 Tg, ° C. −58.6 −57.5 −48.1 −48.1 −45.0 −40.3−40.3

Examples 1-50

Polymer blend compositions were prepared comprising a firstethylene-based copolymer, a second ethylene-based copolymer, and a thirdethylene-based copolymer, all of which were selected from the polymerslisted in Table 1. The blends were made by melt blending in a Brabendermixer having an internal cavity of 250 ml at a temperature of from about120 to about 150° C. for 3 to 5 minutes using low shear blades rotatingat a speed of 15 to 20 rpm. The ethylene-based copolymers were protectedduring the mixing operation with a nitrogen blanket and by the additionof 1000 ppm of a 3:1 mixture of Irganox 1076 and Irgafos 168 (bothavailable from BASF Corporation) before blending. The compositions ofthe resulting polymer blends are set forth in Table 2 below, and theamounts of each component are given in grams.

TABLE 2 Example No. EA2 EA1 EB1 EC1 EC2 EB2 EC3 1 240 120 40 2 200 12080 3 160 120 120 4 120 120 160 5 80 120 200 6 240 120 40 7 200 120 80 8160 120 120 9 120 120 160 10 80 120 200 11 160 200 40 12 120 200 80 1380 200 120 14 160 200 40 15 120 200 80 16 80 200 120 17 280 80 40 18 28080 40 19 280 40 80 20 280 40 80 21 240 120 40 22 240 120 40 23 240 80 8024 240 80 80 25 240 40 120 26 240 40 120 27 200 160 40 28 200 160 40 29200 120 80 30 200 120 80 31 200 80 120 32 200 80 120 33 200 40 160 34200 40 160 35 160 200 40 36 160 200 40 37 160 160 80 38 160 160 80 39160 120 120 40 160 120 120 41 160 80 160 42 160 80 160 43 120 240 40 44120 240 40 45 120 200 80 46 120 200 80 47 120 160 120 48 120 160 120 49120 120 160 50 120 120 160

Molecular weight, thermal properties, and other characteristics of thepolymer blends of Examples 1-50 are given in Table 3, below.

TABLE 3 MFR, g/10 min DSC: 1^(st) Heat DSC: 2^(nd) Heat Ex. (2.16 kg,Mw, Tm, Hf, Tm, Hf, Tm, ° C. Tg, No. 230° C.) FTIR g/mol Mw/Mn ° C. J/g° C. J/g (onset) ° C. 1 54.45 43365 2.27 23.1 15.0 23.1 15.0 −34.0 −57.12 56.92 42001 2.19 23.8 21.8 23.8 21.8 −37.4 −56.8 3 59.95 40998 2.1925.1 32.8 25.1 32.8 −40.1 −56.8 4 61.43 37615 2.27 28.7 36.4 28.7 36.4−36.3 −57.1 5 64.25 35251 2.23 29.1 44.0 29.1 44.0 −34.2 −57.1 6 54.2742868 2.30 26.6 17.1 26.6 17.1 −31.0 −57.2 7 58.11 44370 2.21 35.7 16.835.7 16.8 −15.0 −57.1 8 60.99 43775 2.26 39.5 34.7 39.5 34.7 −34.3 −56.99 64.43 42444 2.21 40.3 36.5 40.3 36.5 −26.9 −57.3 10 66.78 43449 2.2141.5 47.6 41.5 47.6 −32.2 −56.9 11 58.99 39517 2.25 22.1 27.9 22.1 27.9−37.5 −57.0 12 61.64 39076 2.25 25.1 29.3 25.1 29.3 −32.9 −56.8 13 63.7737498 2.37 24.6 40.3 24.6 40.3 −37.8 −56.9 14 60.69 44150 2.19 23.7 30.523.7 30.5 −38.0 −56.9 15 62.85 40363 2.27 25.8 38.0 25.8 38.0 −37.3−57.0 16 65.32 40637 2.29 30.2 44.1 30.2 44.1 −35.8 −57.0 17 5.438054.65 47.8 11.5 26.1 20.1 −50.7 −57.7 18 5.2340 54.81 51.9 15.8 32.010.6 −39.0 −57.9 19 5.0480 56.73 48.3 22.9 47.6 18.2 −37.5 −58.0 204.9280 56.40 52.4 18.8 51.1 15.2 −38.0 −58.1 21 5.4150 58.30 45.7 31.823.6 27.1 −50.4 −57.8 22 5.1410 56.42 51.5 14.5 18.0 12.6 −31.3 −57.8 234.9690 58.21 47.4 32.5 43.2 29.7 −49.4 −57.9 24 4.8310 57.22 51.7 21.451.8 16.0 −24.1 −57.9 25 4.9050 59.58 48.6 40.0 50.1 32.0 −50.4 −58.1 264.6580 57.37 n/a n/a n/a n/a n/a n/a 27 5.3270 59.10 47.1 27.5 24.1 22.9−39.3 −57.8 28 5.0790 58.58 49.0 16.2 15.2 19.6 −41.2 −58.0 29 4.928060.27 48.2 33.3 41.5 20.4 −23.5 −57.7 30 4.8980 59.13 48.9 18.7 46.116.2 −21.7 −57.8 31 4.6240 60.82 49.3 26.5 49.3 23.4 −15.0 −58 32 4.518061.11 50.1 24.7 50.6 21.0 −14.1 −57.8 33 4.2340 63.66 51.4 43.3 52.326.2 −11.3 −57.9 34 4.3650 61.47 50.1 31.8 52.1 25.0 −13.4 −58.0 355.3000 61.30 46.6 30.7 25.1 26.2 −36.7 −57.6 36 5.0550 60.19 48.8 15.817.4 18.1 −32.0 −57.6 37 4.9490 62.41 47.9 34.1 30.4 26.8 −31.8 −57.7 384.7130 60.43 48.9 23.3 20.7 21.4 −27.2 −57.7 39 4.5570 64.59 48.1 42.745.9 27.1 −24.3 −57.9 40 4.6380 62.75 41 4.2630 64.58 48.5 46.1 48.732.3 −27.6 −57.6 42 4.1960 62.80 43 5.7060 61.72 49.0 23.0 23.1 27.3−33.8 −57.7 44 4.9250 61.83 45 5.0010 63.28 50.1 28.2 28.5 31.1 −32.0−57.6 46 4.8630 61.82 47 4.6630 64.36 50.4 37.6 41.0 35.6 −32.0 −57.5 484.3740 63.47 49 4.3840 65.24 50.9 34.4 47.7 35.6 −21.9 −57.5 50 54.4543365 2.27 23.1 15.0 23.1 15.0 −34.0 −57.1

Tables 2 and 3 show the compositionally disperse and crystallinitydisperse blends of the ethylene-based copolymers described herein.

Examples 51-100

10W-50 lubricating oil compositions were prepared comprising theethylene-based copolymer blends of Examples 1-50. All of the lubricatingoil formulations comprised the following: 52 g of a group 11 lubricatingoil basestock having a viscosity of 4.5 cSt, 30.6 g of a group 11lubricating oil basestock having a viscosity of 6.1 cSt, 1.4 g of theinventive polymer blend composition of one of Examples 1-50, 14 g of anadditive package (Infineum D3426), 0.7 g of a magnesium sulfonateadditive having a base number of 400 (Infineum 9340), 1.0 g of a calciumsulfonate additive having a base number of 300 (Infineum 9330), and 0.3g of a pour point depressant (Infineum V387). Viscosity characteristicsof the resulting compositions were tested as follows. Kinematicviscosity (KV) at 100° C. was determined according to ASTM D445-5.Apparent viscosity was measured using a cold cranking simulator (CCS) at−20° C. and −25° C. according to ASTM D5293-4 and ASTM D5293-5,respectively. Yield stress and viscosity were determined using a minirotary viscometer (MRV) at −25° C. and −30° C. according to ASTM D4684-4(−25° C.) and ASTM D4684-5 (−30° C.). Results of these tests arereported in Table 4, below.

TABLE 4 Yield Stress, MRV Yield Stress, MRV Pour Visual Ex. KV, cSt CCS,cP CCS, cP MRV Visc., cP MRV Visc., cP Point, Gelation No. (100° C.)(−20° C.) (−25° C.) (−25° C.) (−25° C.) (−30° C.) (−30° C.) ° C. Rating51 18.11 3,320 6,490 <35 14,800 <35 40,900 −34 2 52 18.03 3,210 6,460<35 14,300 <35 39,300 −36 4 53 17.76 3,140 6,350 <35 13,500 <35 37,900−36 4 54 17.52 3,090 6,260 <35 12,100 <35 36,500 −35 4 55 17.47 3,0406,200 <35 12,100 <35 36,300 −36 4 56 18.80 3,290 6,660 <35 15,000 <3538,700 −37 0 57 18.89 3,230 6,590 <35 13,700 <35 37,600 −36 0 58 19.003,170 6,400 <35 12,700 <35 34,900 −36 59 19.38 3,110 6,370 <35 10,500<35 29,800 −38 4 60 19.43 3,050 6,400 <35 11,200 <35 32,200 −36 4 6117.75 3,160 6,300 <35 14,300 <35 40,800 −37 4 62 17.43 3,110 6,140 <3512,800 <35 37,700 −35 4 63 17.57 3,080 6,130 <35 12,900 <35 38,700 −35 464 18.32 3,210 6,330 <35 13,300 <35 38,600 −36 3 65 18.40 3,140 6,310<35 12,600 <35 35,900 −36 3 66 18.76 3,090 6,220 <35 11,900 <35 34,600−37 3 67 18.61 3,590 7,020 <35 15,800 <35 40,600 −38 68 19.53 3,6707,170 <35 16,800 <35 45,000 −35 69 18.77 3,550 7,050 <35 15,400 <3540,600 −38 70 19.12 7,080 7,080 <35 16,600 <35 42,200 −37 71 19.38 3,5807,140 <35 18,500 <35 50,000 −36 72 18.63 3,480 7,000 <35 15,500 <3543,000 −33 73 18.85 3,480 6,840 <35 14,300 <35 43,200 −34 74 19.21 3,4806,950 <35 14,400 <35 43,100 −31 75 19.29 3,460 6,960 <35 15,100 <3548,000 −35 76 18.21 3,390 6,850 <35 13,800 <35 40,400 −33 77 18.75 3,4206,920 <35 14,100 <35 40,300 −31 78 19.00 3,400 6,870 <35 14,000 <3542,300 −32 79 19.28 3,410 6,960 <35 14,500 <35 46,300 −30 80 18.20 3,3406,800 <35 13,100 <35 39,500 −34 81 18.57 3,350 6,830 <35 12,500 <3536,600 −32 82 18.98 3,360 6,800 <35 12,500 <35 37,600 −36 83 19.39 3,4106,980 <35 13,300 <35 44,300 −34 84 18.90 3,500 6,820 <35 15,100 <3539,700 −37 85 19.29 3,510 6,840 <35 15,700 <35 42,300 −37 86 19.06 3,4306,830 <35 15,000 <35 39,900 −37 87 19.22 3,430 6,750 <35 14,900 <3538,800 −37 88 19.30 3,400 6,720 <35 15,100 <35 41,800 −35 89 19.02 3,3706,650 <35 14,800 <35 41,200 −29 90 19.23 3,360 6,720 <35 14,100 <3539,200 −31 91 19.40 3,380 6,710 <35 14,700 <35 41,100 −31 92 19.46 3,3206,690 <35 14,700 <35 44,500 −31 93 19.05 3,360 6,670 <35 15,200 <3544,700 −29 94 19.09 3,330 6,580 <35 13,900 <35 38,100 −32 95 19.16 3,2906,680 <35 13,600 <35 38,500 −34 96 19.27 3,300 6,610 <35 14,400 <3542,900 −34 97 19.49 3,370 6,740 <35 15,400 <70 50,700 −34 98 19.09 3,3106,680 <35 13,900 <35 40,500 −35 99 19.65 3,320 6,640 <35 12,300 <3536,600 −37 100 19.30 3,270 6,520 <35 13,000 <35 39,400 −36

Examples 101-125

Lubricating oil compositions were prepared comprising selectedethylene-based copolymer blends of Examples 1-50. All of the lubricatingoil formulations comprised 1 wt % of the ethylene-based copolymer blendin a Group I basestock (Americas Core 150, available from Imperial OilLtd.) having the following lubricant properties: kinematic viscosity(KV) at 100° C. (ASTM D445-5) of 5.189 cSt, KV at 40° C. (ASTM D445-3)of 29 cSt (min), viscosity index (ASTM D2270) of 95 (min), flash point(ASTM D92) of 210° C. (min), pour point (ASTM D97) of −15° C. (max), andNoack volatility (ASTM D5800) of 20 wt % (max). For each formulation,shear stability properties (reflected by the Kurt Orbahn (KO) test at 30and 90 cycles) and thickening efficiency (TE) were measured. Results ofthese tests are reported in Table 5, below.

TABLE 5 Example No. Blend No. KO (30 cycles) KO (90 cycles) TE 101 120.54 25.04 1.98 102 2 21.00 24.60 1.95 103 3 18.90 22.96 1.92 104 417.82 21.59 1.88 105 5 17.02 20.21 1.86 106 6 24.06 28.19 2.04 107 723.25 28.35 2.03 108 8 21.41 26.25 2.05 109 9 21.36 26.03 2.10 110 1022.44 26.03 2.10 111 11 19.42 23.51 1.92 112 12 16.31 20.55 1.87 113 1312.69 16.99 1.85 114 14 20.75 25.09 1.96 115 15 20.62 25.09 1.99 116 1620.11 24.62 2.04 117 17 23.24 27.53 1.98 118 27 19.79 23.42 1.93 119 3720.15 24.07 1.98 120 43 17.90 22.22 1.91 121 18 20.70 25.58 1.98 122 2223.93 28.57 2.06 123 28 22.63 27.08 2.06 124 38 20.58 26.95 2.08 125 4620.81 25.96 2.07

Certain embodiments and features have been described using a set ofnumerical upper limits and a set of numerical lower limits. It should beappreciated that ranges from any lower limit to any upper limit arecontemplated unless otherwise indicated. Certain lower limits, upperlimits and ranges appear in one or more claims below. All numericalvalues are “about” or “approximately” the indicated value, and take intoaccount experimental error and variations that would be expected by aperson having ordinary skill in the art.

Various terms have been defined above. To the extent a term used in aclaim is not defined above, it should be given the broadest definitionpersons in the pertinent art have given that term as reflected in atleast one printed publication or issued patent. Furthermore, allpatents, test procedures, and other documents cited in this applicationare fully incorporated by reference to the extent such disclosure is notinconsistent with this application and for all jurisdictions in whichsuch incorporation is permitted.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A polymer blend composition comprising a first ethylene-basedcopolymer, a second ethylene-based copolymer, and a third ethylene-basedcopolymer, wherein: (a) the first copolymer has an ethylene content fromabout 35 to about 55 wt %; (b) the second copolymer has an ethylenecontent from about 55 to about 85 wt %; (c) the third copolymer has anethylene content from about 65 to about 85 wt %; (d) the ethylenecontent of the second copolymer is at least about 15 wt % greater thanthe ethylene content of the first copolymer and the ethylene content ofthe third copolymer is at least about 5 wt % greater than the ethylenecontent of the second copolymer; (e) the first, second, and thirdcopolymers have a weight-average molecular weight (Mw) less than orequal to about 130,000; (f) the ratio of the melt index of the firstcopolymer to the melt index of the second copolymer is less than orequal to about 3.0 and the ratio of the melt index of the firstcopolymer to the melt index of the third copolymer is less than or equalto about 3.0; and (g) the composition comprises from about 15 to about85 wt % of the first copolymer, based on the total weight of the first,second, and third copolymers.
 2. The polymer blend composition of claim1, wherein the first copolymer has an ethylene content from about 40 toabout 55 wt %, the second copolymer has an ethylene content from about55 to about 73 wt %, and the third copolymer has an ethylene contentfrom about 70 to about 85 wt %.
 3. The polymer blend composition ofclaim 2, wherein the first copolymer has an ethylene content from about45 to about 53 wt %, the second copolymer has an ethylene content fromabout 65 to about 73 wt %, and the third copolymer has an ethylenecontent from about 71 to about 85 wt %.
 4. The polymer blend compositionof claim 1, wherein the first, second, and third copolymers eachcomprise one or more comonomers selected from the group consisting ofC₃-C₂₀ alpha-olefins.
 5. The polymer blend composition of claim 1,wherein the ethylene content of the second copolymer is at least about18 wt % greater than the ethylene content of the first copolymer and theethylene content of the third copolymer is at least about 6 wt % greaterthan the ethylene content of the second copolymer.
 6. The polymer blendcomposition of claim 5, wherein the ethylene content of the secondcopolymer is at least about 22 wt % greater than the ethylene content ofthe first copolymer and the ethylene content of the third copolymer isat least about 8 wt % greater than the ethylene content of the secondcopolymer.
 7. The polymer blend composition of claim 1, wherein thecomposition comprises from about 25 to about 75 wt % of the firstcopolymer, based on the total weight of the first, second, and thirdcopolymers.
 8. The polymer blend composition of claim 7, wherein thecomposition comprises from about 35 to about 65 wt % of the firstcopolymer, based on the total weight of the first, second, and thirdcopolymers.
 9. A polymer blend composition comprising a firstethylene-based copolymer, a second ethylene-based copolymer, and a thirdethylene-based copolymer, wherein: (a) the first copolymer has a firstmelt heat of fusion from about 0 to about 30 J/g; (b) the secondcopolymer has a first melt heat of fusion from about 30 to about 50 J/g;(c) the third copolymer has a first melt heat of fusion from about 40 toabout 85 J/g; (d) the heat of fusion of the third copolymer is at leastabout 5 J/g greater than the heat of fusion of the second copolymer; (e)the first, second, and third copolymers have a weight-average molecularweight (Mw) less than or equal to about 130,000; (f) the ratio of themelt index of the first copolymer to the melt index of the secondcopolymer is less than or equal to about 3.0 and the ratio of the meltindex of the first copolymer to the melt index of the third copolymer isless than or equal to about 3.0; and (g) the composition comprises fromabout 15 to about 85 wt % of the first copolymer, based on the totalweight of the first, second, and third copolymers.
 10. The polymer blendcomposition of claim 9, wherein the first copolymer has a first meltheat of fusion from about 0 to about 15 J/g, the second copolymer has afirst melt heat of fusion from about 35 to about 48 J/g, and the thirdcopolymer has a first melt heat of fusion from about 55 to about 75 J/g.11. The polymer blend composition of claim 10, wherein the firstcopolymer has a first melt heat of fusion from about 0 to about 10 J/g,the second copolymer has a first melt heat of fusion from about 40 toabout 48 J/g, and the third copolymer has a first melt heat of fusionfrom about 65 to about 75 J/g.
 12. The polymer blend composition ofclaim 9, wherein the first, second, and third copolymers each compriseone or more comonomers selected from the group consisting of C₃-C₂₀alpha-olefins.
 13. The polymer blend composition of claim 9, wherein theheat of fusion of the third copolymer is at least about 8 J/g greaterthan the heat of fusion of the second copolymer.
 14. The polymer blendcomposition of claim 13, wherein the heat of fusion of the thirdcopolymer is at least about 12 J/g greater than the heat of fusion ofthe second copolymer.
 15. The polymer blend composition of claim 9,wherein the composition comprises from about 25 to about 75 wt % of thefirst copolymer, based on the total weight of the first, second, andthird copolymers.
 16. The polymer blend composition of claim 15, whereinthe composition comprises from about 35 to about 65 wt % of the firstcopolymer, based on the total weight of the first, second, and thirdcopolymers.
 17. A lubricating oil composition comprising a lubricatingoil basestock, a first ethylene-based copolymer, a second ethylene-basedcopolymer, and a third ethylene-based copolymer wherein: (a) the firstcopolymer has an ethylene content from about 35 to about 55 wt %; (b)the second copolymer has an ethylene content from about 55 to about 85wt %; (c) the third copolymer has an ethylene content from about 65 toabout 85 wt %; (d) the ethylene content of the third copolymer is atleast about 5 wt % greater than the ethylene content of the secondcopolymer; (e) the first, second, and third copolymers have aweight-average molecular weight (Mw) less than or equal to about130,000; (f) the ratio of the melt index of the first copolymer to themelt index of the second copolymer is less than or equal to about 3.0and the ratio of the melt index of the first copolymer to the melt indexof the third copolymer is less than or equal to about 3.0; and (g) thecomposition comprises from about 15 to about 85 wt % of the firstcopolymer, based on the total weight of the first, second, and thirdcopolymers.
 18. The lubricating oil composition of claim 17, wherein thefirst copolymer has an ethylene content from about 45 to about 53 wt %,the second copolymer has an ethylene content from about 65 to about 73wt %, and the third copolymer has an ethylene content from about 71 toabout 85 wt %.
 19. The lubricating oil composition of claim 17, whereinthe first, second, and third copolymers each comprise one or morecomonomers selected from the group consisting of C₃-C₂₀ alpha-olefins.20. The lubricating oil composition of claim 17, wherein the ethylenecontent of the second copolymer is at least about 18 wt % greater thanthe ethylene content of the first copolymer and the ethylene content ofthe third copolymer is at least about 6 wt % greater than the ethylenecontent of the second copolymer.
 21. A lubricating oil compositioncomprising a lubricating oil basestock, a first ethylene-basedcopolymer, a second ethylene-based copolymer, and a third ethylene-basedcopolymer, wherein: (a) the first copolymer has a first melt heat offusion from about 0 to about 30 J/g; (b) the second copolymer has afirst melt heat of fusion from about 30 to about 50 J/g; (c) the thirdcopolymer has a first melt heat of fusion from about 40 to about 85 J/g;(d) the heat of fusion of the third copolymer is at least about 5 J/ggreater than the heat of fusion of the second copolymer; (e) the first,second, and third copolymers have a weight-average molecular weight (Mw)less than or equal to about 130,000; (f) the ratio of the melt index ofthe first copolymer to the melt index of the second copolymer is lessthan or equal to about 3.0 and the ratio of the melt index of the firstcopolymer to the melt index of the third copolymer is less than or equalto about 3.0; and (g) the composition comprises from about 15 to about85 wt % of the first copolymer, based on the total weight of the first,second, and third copolymers.
 22. The lubricating oil composition ofclaim 21, wherein the first copolymer has a first melt heat of fusionfrom about 0 to about 10 J/g, the second copolymer has a first melt heatof fusion from about 40 to about 48 J/g, and the third copolymer has afirst melt heat of fusion from about 65 to about 75 J/g.
 23. Thelubricating oil composition of claim 21, wherein the first, second, andthird copolymers each comprise one or more comonomers selected from thegroup consisting of C₃-C₂₀ alpha-olefins.
 24. The lubricating oilcomposition of claim 21, wherein the ethylene content of the secondcopolymer is at least about 18 wt % greater than the ethylene content ofthe first copolymer and the ethylene content of the third copolymer isat least about 6 wt % greater than the ethylene content of the secondcopolymer.